molybdenum ditelluride

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid =

| Name = Molybdenum ditelluride

| ImageFile2 = MoTe2 crystal.jpg

| ImageFile1 =

{{chem2|Mo^{4+}(Te^{2-})2}}

| ImageSize =

| ImageName = Molybdenum ditelluride

| IUPACName = bis(tellanylidene)molybdenum

| OtherNames = molybdenum(IV) telluride

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 58270

| InChI = 1/Mo.2Te/rMoS2/c2-1-3

| InChIKey = HITXEXPSQXNMAN-UHFFFAOYSA-N

| ChEBI_Ref =

| ChEBI =

| EC_number = 235-028-4

| SMILES = [Te]=[Mo]=[Te]

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1Te/Mo.2Te

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey =

| CASNo = 12058-20-7

| CASNo_Ref = {{cascite|correct|CAS}}

| RTECS =

| PubChem = 64728

}}

|Section2={{Chembox Properties

| Mo=1|Te=2

| MolarMass = 351.14 g/mol{{RubberBible92nd|page=4.76}}

| Appearance = black/lead-gray solid

| Density = 7.7 g/cm3

| MeltingPtC =

| MeltingPt_notes = decomposes

| BandGap = 1.1 eV (direct, monolayer){{cite journal|last1=Ruppert|first1=Claudia|last2=Aslan|first2=Ozgur Burak|last3=Heinz|first3=Tony F.|title=Optical Properties and Band Gap of Single- and Few-Layer MoTe2 Crystals|journal=Nano Letters|date=12 November 2014|volume=14|issue=11|pages=6231–6236|doi=10.1021/nl502557g|pmid=25302768|bibcode=2014NanoL..14.6231R}}
0.9 eV (indirect, bulk){{cite journal|doi=10.1103/PhysRevB.85.033305|title=Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-MX2 semiconductors (M = Mo, W; X = S, Se, Te)|journal=Physical Review B|volume=85|issue=3|pages=033305|year=2012|last1=Yun|first1=Won Seok|last2=Han|first2=S. W.|last3=Hong|first3=Soon Cheol|last4=Kim|first4=In Gee|last5=Lee|first5=J. D.|bibcode=2012PhRvB..85c3305Y}}

| Solubility = insoluble

| SolubleOther = decomposed by nitric acid
insoluble in non-oxidising acids

}}

|Section3={{Chembox Structure

| CrystalStruct = hP6, P63/mmc, No. 194 (α or 2H)

mP12, P21/m, No. 11 (β or 1T)

| LattConst_a =

| LattConst_c =

| Coordination =

}}

|Section7={{Chembox Hazards

| ExternalSDS =

| NFPA-H =

| NFPA-F =

| NFPA-R =

}}

|Section8={{Chembox Related

| OtherAnions = molybdenum(IV) oxide molybdenum disulfide molybdenum diselenide

| OtherCations = tungsten ditelluride, vanadium ditelluride

| OtherFunction =

| OtherFunction_label =

}}

}}Molybdenum(IV) telluride, molybdenum ditelluride or just molybdenum telluride is an inorganic compound with formula MoTe2. It is a semiconductor, and can fluoresce. It is one of the transition metal dichalcogenides. As a semiconductor the band gap lies in the infrared region. It is a potential use as a semiconductor in electronics or an infrared detector. MoTe2 is black.{{cite journal|last1=Balakrishnan|first1=K.|last2=Ramasamy|first2=P.|title=Study of anomalous electrical behaviour of molybdenum ditelluride single crystals|journal=Journal of Crystal Growth|date=March 1994|volume=137|issue=1–2|pages=309–311|doi=10.1016/0022-0248(94)91291-2|bibcode=1994JCrGr.137..309B}} Although sometimes described as Mo4+, 2Te2-, it is not ionic but highly covalent.

Preparation

MoTe2 can be prepared by heating the correct ratio of the elements together at 1100 °C in a vacuum.{{cite journal|last1=Puotinen|first1=D.|last2=Newnham|first2=R. E.|title=The crystal structure of MoTe|journal=Acta Crystallographica|date=1 June 1961|volume=14|issue=6|pages=691–692|doi=10.1107/s0365110x61002084|doi-access=free|bibcode=1961AcCry..14..691P }} Another method is via vapour deposition, where molybdenum and tellurium are volatilised in bromine gas and then deposited. Using bromine results in forming an n-type semiconductor, whereas using tellurium only results in a p-type semiconductor.{{cite journal|last1=Bernède|first1=J.C|last2=Amory|first2=C|last3=Assmann|first3=L|last4=Spiesser|first4=M|title=X-ray photoelectron spectroscopy study of MoTe2 single crystals and thin films|journal=Applied Surface Science|date=December 2003|volume=219|issue=3–4|pages=238–248|doi=10.1016/s0169-4332(03)00697-4|bibcode=2003ApSS..219..238B}}

The amount of tellurium in molybdenum ditelluride can vary from 1.97 to 2.{{cite journal|last1=Morsli|first1=M|last2=Bonnet|first2=A|last3=Jousseaume|first3=V|last4=Cattin|first4=L|last5=Conan|first5=A|last6=Zoaeter|first6=M|title=Tellurium depletion electrical effects in MoTe2−X single crystals doped with bromine|journal=Journal of Materials Science|date=1997|volume=32|issue=9|pages=2445–2449|doi=10.1023/a:1018569510512|bibcode=1997JMatS..32.2445M|s2cid=91726610}} Excess tellurium deposited during this process can be dissolved off with sulfuric acid.{{cite journal|last1=Kettaf|first1=M.|last2=Conan|first2=A.|last3=Bonnet|first3=A.|last4=Bernede|first4=J.C.|title=Electrical properties of molybdenum ditelluride thin films|journal=Journal of Physics and Chemistry of Solids|date=January 1990|volume=51|issue=4|pages=333–341|doi=10.1016/0022-3697(90)90116-w|bibcode=1990JPCS...51..333K}}

It can crystallise in two dimensional sheets which can be thinned down to monolayers that are flexible and almost transparent.

By annealing molybdenum film in a tellurium vapour at 850 to 870 K for several hours, a thin layer of MoTe2 is formed.{{cite journal|last1=Bernede|first1=J.C.|last2=Pouzet|first2=J.|last3=Manai|first3=N.|last4=Mouais|first4=A.Ben|title=Structural characterization of synthesized molybdenum ditelluride thin films|journal=Materials Research Bulletin|date=January 1990|volume=25|issue=1|pages=31–42|doi=10.1016/0025-5408(90)90159-y}}

An amorphous form can be produced by sonochemically reacting molybdenum hexacarbonyl with tellurium dissolved in decalin.{{cite journal|last1=Qiu|first1=Longhui|last2=Pol|first2=Vilas G.|last3=Wei|first3=Yun|last4=Gedanken|first4=Aharon|title=A two-step process for the synthesis of MoTe2 nanotubes: combining a sonochemical technique with heat treatment|journal=Journal of Materials Chemistry|date=2003|volume=13|issue=12|pages=2985|doi=10.1039/B308368C}}

Molybdenum ditelluride can be formed by electrodeposition from a solution of molybdic acid (H2MoO4) and tellurium dioxide (TeO2). The product can be electroplated on stainless steel or indium tin oxide.{{cite journal|last1=Ying|first1=Lim Mei|last2=Mazlan|first2=Nor Hamizah Bt.|last3=Anand|first3=T. Joseph Sahaya|title=Electrodeposited MoTe2 Thin Films for Photoelectrochemical (PEC) Cell Applications|journal=Malaysian Technical Universities International Conference on Engineering & Technology|date=2011|url=http://eprints2.utem.edu.my/10142/1/MUiCET_2011_Anand.pdf|access-date=13 May 2015|archive-url=https://web.archive.org/web/20150518100901/http://eprints2.utem.edu.my/10142/1/MUiCET_2011_Anand.pdf|archive-date=18 May 2015|url-status=dead}}

Tellurization of thin Mo film at 650 °C by chemical vapor deposition (CVD) leads to the hexagonal, semiconducting α-form (2H-MoTe2) while using MoO3 film produces the monoclinic, semimetallic β-form (1T'-MoTe2) at the same temperature of 650 °C.{{Cite journal|last1=Fraser|first1=James P.|last2=Masaityte|first2=Liudvika|last3=Zhang|first3=Jingyi|last4=Laing|first4=Stacey|last5=Moreno-López|first5=Juan Carlos|last6=McKenzie|first6=Adam F.|last7=Graham|first7=Duncan|last8=Kazakova|first8=Olga|last9=Pichler|first9=Thomas|last10=MacLaren|first10=Donald|last11=Ganin|first11=Alexey Y.|date=2020-07-24|title=Selective phase growth and precise-layer control in MoTe 2|journal=Communications Materials|language=en|volume=1|issue=1|page=48|doi=10.1038/s43246-020-00048-4|bibcode=2020CoMat...1...48F|issn=2662-4443|doi-access=free}}

Physical properties

Very thin crystals of MoTe2 can be made using sticky tape. When they are thin around 500 nm thick red light can be transmitted. Even thinner layers can be orange or transparent. An absorption edge occurs in the spectrum with wavelengths longer than 6720 Å transmitted and shorter wavelengths heavily attenuated. At 77 K this edge changes to 6465 Å. This corresponds to deep red.

=Infrared=

MoTe2 reflects about 43% in the infrared band but has a peak at 234.5 cm−1 and a minimum at 245.8 cm−1.{{cite journal|last1=Wieting|first1=T.J.|last2=Grisel|first2=A.|last3=Lévy|first3=F.|title=Interlayer bonding and localized charge in MoSe2 and α-MoTe2|journal=Physica B+C|date=January 1980|volume=99|issue=1–4|pages=337–342|doi=10.1016/0378-4363(80)90256-9|bibcode=1980PhyBC..99..337W}}

As the temperature is lowered the absorption bands become narrower. At 77 K there are absorption peaks at 1.141, 1.230, 1.489, 1.758, 1.783, 2.049, 2.523, 2.578, and 2.805 eV.{{cite journal|last1=Davey|first1=B.|last2=Evans|first2=B. L.|title=The optical properties of MoTe2 and WSe2|journal=Physica Status Solidi A|date=16 October 1972|volume=13|issue=2|pages=483–491|doi=10.1002/pssa.2210130217|bibcode=1972PSSAR..13..483D}}

Exciton energy levels are at 1.10 eV, called A, and 1.48 eV, called B, with a difference of 0.38 eV.{{cite journal|last1=Coehoorn|first1=R.|last2=Haas|first2=C.|last3=de Groot|first3=R. A.|title=Electronic structure of MoSe2, MoS2, and WSe2. II. The nature of the optical band gaps|journal=Physical Review B|date=1987|volume=35|issue=12|pages=6203–6206|doi=10.1103/PhysRevB.35.6203|pmid=9940851|bibcode=1987PhRvB..35.6203C|url=https://pure.rug.nl/ws/files/3393107/1987PhysRevBCoehoorn2.pdf|hdl=11370/2770eade-489b-4f2f-bb38-19f572f28300|hdl-access=free}}

=Raman spectrum=

The Raman spectrum has four lines with wavenumbers of 25.4, 116.8, 171.4, and a double one at 232.4 and 234.5 cm−1. The peak at 234.5 cm−1 is due to E12g mode, especially in nanolayers, but the thicker forms and the bulk has the second peak at 232.4 cm−1 also perhaps due to the E21u phonon mode. The peak near 171.4 cm−1 comes from the A1g. 138 and 185 cm−1 peaks may be due to harmonics. B12g is assigned to a peak around 291 cm−1 in nanolayers with few layers. The E12g frequency increases as the number of layers decreases to 236.6 cm−1 for single layer. The A1g mode lowers its frequency as the number of layers decreases, becoming 172.4 cm−1 for the monolayer.

=Crystal form=

File:Molybdenite-3D-balls.png

File:MoTe2 1T and Td structures.png

File:MoTe2 STEM.jpg

MoTe2 commonly exists in three crystalline forms with rather similar layered structures: hexagonal α (2H-MoTe2), monoclinic β (1T-MoTe2) and orthorhombic β' (1T'-MoTe2). At room temperature it crystallises in the hexagonal system similar to molybdenum disulfide. Crystals are platy or flat. MoTe2 has unit cell sizes of a=3.519 Å c=13.964 Å and a specific gravity of 7.78 g·cm−3. Each molybdenum atom is surrounded by six tellurium atoms in a trigonal prism with the separation of these Mo and Te atoms being 2.73 Å. This results in sublayers of molybdenum sandwiched between two sublayers of tellurium atoms, and then this three layer structure is stacked. Each layer is 6.97 Å thick.{{cite journal|last1=Frindt|first1=R.F.|title=The optical properties of single crystals of WSe2 and MoTe2|journal=Journal of Physics and Chemistry of Solids|date=September 1963|volume=24|issue=9|pages=1107–1108|doi=10.1016/0022-3697(63)90024-6|bibcode=1963JPCS...24.1107F}} Within this layer two tellurium atoms in the same sublayer subtend an angle of 80.7°. The tellurium atoms on one sublayer are directly above those in the lower sublayer, and they subtend an angle of 83.1° at the molybdenum atom. The other Te-Mo-Te angle across sublayers is 136.0°. The distance between molybdenum atoms within a sublayer is 3.518 Å. This is the same as the distance between tellurium atoms in a sublayer. The distance between a tellurium atom in one sublayer and the atom in the other sublayer is 3.60 Å.{{cite journal|last1=Knop|first1=Osvald|last2=MacDonald|first2=Roderick D.|title=Chalkogenides of the Transition Elements III Molybdenum Ditelluride|journal= Canadian Journal of Chemistry|date=1961|volume=39|issue=4|pages=897–905|doi=10.1139/v61-110|doi-access=free|bibcode=1961CaJCh..39..897K }}

The layers are only bonded together with van der Waals force.{{cite journal|last1=Agarwal|first1=M. K.|last2=Capers|first2=M. J.|title=Dislocations in molybdenum ditelluride|journal=Journal of Applied Crystallography|date=1 October 1976|volume=9|issue=5|pages=407–410|doi=10.1107/s0021889876011710|bibcode=1976JApCr...9..407A }} The distance between tellurium atoms across the layers is 3.95 Å. The tellurium atom at the bottom of one layer is aligned with the centre of a triangle of tellurium atoms on the top of the layer below. The layers are thus in two different positions. The crystal is very easily cleaved on the plane between the three layer sheets. The sizes change with temperature, at 100 K a=3.492 Å and at 400 K is 3.53 Å. In the same range c changes from 13.67 Å to 14.32 Å due to thermal expansion.{{cite journal|last1=Agarwal|first1=M. K.|last2=Capers|first2=M. J.|title=The measurement of the lattice parameters of molybdenum ditelluride|journal=Journal of Applied Crystallography|date=1 April 1972|volume=5|issue=2|pages=63–66|doi=10.1107/s0021889872008787|bibcode=1972JApCr...5...63A }} The hexagonal form is also called 2H-MoTe2, where "H" stands for hexagonal, and "2" means that the layers are in two different positions. Every second layer is positioned the same.

At temperatures above 900 °C MoTe2 crystallises in the monoclinic 1T form (β–MoTe2), with space group P21/m with unit cell sizes of a=6.33 Å b=3.469 Å and c=13.86 Å with the angle β=93°55′. The high-temperature form has rod shaped crystals. The measured density of this polymorph is 7.5 g·cm−3, but in theory it should be 7.67 g·cm−3. Tellurium atoms form a distorted octahedron around the molybdenum atoms.{{cite journal|last1=Brown|first1=B. E.|title=The crystal structures of WTe and high-temperature MoTe|journal=Acta Crystallographica|date=1 February 1966|volume=20|issue=2|pages=268–274|doi=10.1107/s0365110x66000513|bibcode=1966AcCry..20..268B }} This high-temperature form, termed β–MoTe2 can be quenched to room temperature by rapid cooling.{{cite journal|last1=Revolinsky|first1=E.|last2=Beerntsen|first2=D.J.|title=Electrical properties of α- and β-MoTe2 as affected by stoichiometry and preparation temperature|journal=Journal of Physics and Chemistry of Solids|date=March 1966|volume=27|issue=3|pages=523–526|doi=10.1016/0022-3697(66)90195-8|bibcode=1966JPCS...27..523R}} In this metastable state β-MoTe2 can survive below 500 °C. When metastable β–MoTe2 is cooled below −20 °C, its crystal form changes to orthorhombic. This is because the monoclinic angle c changes to 90°. This form is called β' or, misleadingly, Td.{{cite journal|last1=Manolikas|first1=C.|last2=van Landuyt|first2=J.|last3=Amelinckx|first3=S.|title=Electron microscopy and electron diffraction study of the domain structures, the dislocation fine structure, and the phase transformations in β-MoTe2|journal=Physica Status Solidi A|date=16 May 1979|volume=53|issue=1|pages=327–338|doi=10.1002/pssa.2210530138|bibcode=1979PSSAR..53..327M}}

The transition from α- to β-MoTe2 happens at 820 °C, but if Te is reduced by 5% the required transition temperature increases to 880 °C.{{cite journal|last1=Vellinga|first1=M.B.|last2=de Jonge|first2=R.|last3=Haas|first3=C.|title=Semiconductor to metal transition in MoTe2|journal=Journal of Solid State Chemistry|date=August 1970|volume=2|issue=2|pages=299–302|doi=10.1016/0022-4596(70)90085-x|bibcode=1970JSSCh...2..299V}} K. Ueno and K. Fukushima claim that when the α form is heated in a low or high vacuum that it oxidises to form MoO2 and that reversible phase transitions do not take place.{{cite journal|last1=Ueno|first1=Keiji|last2=Fukushima|first2=Koji|title=Changes in structure and chemical composition of α-MoTe2 and β-MoTe2 during heating in vacuum conditions|journal=Applied Physics Express|date=1 September 2015|volume=8|issue=9|pages=095201|doi=10.7567/APEX.8.095201|bibcode=2015APExp...8i5201U|s2cid=101351376 }}

In bulk, MoTe2 can be produced as a single crystal with difficulty, but can also be made as a powder, as a polycrystalline form, as a thin film, as a nanolayer consisting of a few TeMoTe sheets, a bilayer consisting of two sheets or as a monolayer with one sheet.

Thin nanolayer forms of α-MoTe2 have different symmetry depending on how many layers there are. With an odd number of layers the symmetry group is D13h without inversion, but for an even number of layers, the lattice is the same if inverted and the symmetry group is D33d.

Nanotubes with a 20–60 nm diameter can be made by heat treating amorphous MoTe2.

=Electrical=

N-type bulk α-MoTe2 has an electrical conductivity of 8.3 Ω−1cm−1 with 5×1017 mobile electrons per cubic centimeter. P-type bulk MoTe2 has an electrical conductivity of 0.2 Ω−1cm−1 and a hole concentration of 3.2×1016 cm−3. The peak electrical conductivity is around 235 K, dropping off slowly with decreasing temperatures, but also reducing to a minimum around 705 K. Above 705 K conductivity increases again with temperature. Powdered MoTe2 has a much higher resistance.

β–MoTe2 has a much lower resistivity than α–MoTe2 by more than a thousand times with values around 0.002 Ω·cm. It is much more metallic in nature. In the β form the molybdenum atoms are closer together so that the conduction band overlaps. At room temperature resistivity is 0.000328 Ω·cm.{{cite journal|last1=Zandt|first1=Thorsten|last2=Dwelk|first2=Helmut|last3=Janowitz|first3=Christoph|last4=Manzke|first4=Recardo|title=Quadratic temperature dependence up to 50 K of the resistivity of metallic MoTe2|journal=Journal of Alloys and Compounds|date=September 2007|volume=442|issue=1–2|pages=216–218|doi=10.1016/j.jallcom.2006.09.157}}

Orthorhombic MoTe2 has a resistance about 10% lower than the β form, and the resistance shows hysteresis of several degrees across the transition point around 250 K. The resistance drops roughly linearly with decreasing temperature. At 180 K resistivity is 2.52×10−4 Ω·cm, and at 120 mK the material becomes a superconductor. Since orthorhombic MoTe2 breaks spatial inversion symmetry, it exhibits ferroelectricity which can be coupled to its innate superconductivity. This coupling was leveraged to create a superconducting switch with MoTe2.{{Cite journal |last1=Jindal |first1=Apoorv |last2=Saha |first2=Amartyajyoti |last3=Li |first3=Zizhong |last4=Taniguchi |first4=Takashi |last5=Watanabe |first5=Kenji |last6=Hone |first6=James C. |last7=Birol |first7=Turan |last8=Fernandes |first8=Rafael M. |last9=Dean |first9=Cory R. |last10=Pasupathy |first10=Abhay N. |last11=Rhodes |first11=Daniel A. |date=January 2023 |title=Coupled ferroelectricity and superconductivity in bilayer Td-MoTe2 |url=https://www.nature.com/articles/s41586-022-05521-3 |journal=Nature |language=en |volume=613 |issue=7942 |pages=48–52 |doi=10.1038/s41586-022-05521-3 |pmid=36600069 |issn=1476-4687|arxiv=2304.05443 |s2cid=255457334 }}{{Cite journal |last=Yasuda |first=Kenji |date=January 2023 |title=Electric switch found for a superconductor |url=https://www.nature.com/articles/d41586-022-04491-w |journal=Nature |language=en |volume=613 |issue=7942 |pages=33–34 |doi=10.1038/d41586-022-04491-w|pmid=36600058 |bibcode=2023Natur.613...33Y |s2cid=255467795 }}

At low electric current levels the voltage is proportional to the current in the α form. With high electric currents MoTe2 shows negative resistance, where as the current increases the voltage across the material decreases. This means there is a maximum voltage that can be applied. In the negative resistance region the current must be limited, otherwise thermal runaway will destroy the item made from the material.{{cite journal|last1=Conan|first1=A.|last2=Zoaeter|first2=M.|last3=Goureaux|first3=G.|title=Mechanism of thermal switching in bulk MoTe2−x compounds|journal=Physica Status Solidi A|date=16 December 1976|volume=38|issue=2|pages=505–512|doi=10.1002/pssa.2210380210|bibcode=1976PSSAR..38..505C}}

The Hall constant at room temperature is around 120 cm3/Coulomb for stochiometric α-MoTe2. But as Te is depleted the constant drops to close to 0 for compositions in the range MoTe1.94 to MoTe1.95.{{cite journal|last1=Conan|first1=Alain|last2=Goureaux|first2=Guy|last3=Zoaeter|first3=Mohamed|title=Transport properties of MoTe2−x and MoSe2−x compounds between 130 and 300K|journal=Journal of Physics and Chemistry of Solids|date=April 1975|volume=36|issue=4|pages=315–320|doi=10.1016/0022-3697(75)90029-3|bibcode=1975JPCS...36..315C}}

The Seebeck coefficient is about 450 μV/K at room temperature for pure MoTe2, but this drops to 0 for MoTe1.95. The Seebeck coefficient increases as temperature drops.

=Band gap=

In the bulk α form of MoTe2 the material is a semiconductor with a room temperature indirect band gap of 0.88 eV and a direct band gap of 1.02 eV. If instead of bulk forms, nanolayers are measured, the indirect band gap increases as the number of layers is reduced. α-MoTe2 changes from an indirect to a direct band gap material in very thin slices.{{cite journal|last1=Lezama|first1=Ignacio Gutiérrez|last2=Ubaldini|first2=Alberto|last3=Longobardi|first3=Maria|author3-link=Maria Longobardi (physicist)|last4=Giannini|first4=Enrico|last5=Renner|first5=Christoph|last6=Kuzmenko|first6=Alexey B|last7=Morpurgo|first7=Alberto F|title=Surface transport and band gap structure of exfoliated 2H-MoTe2 crystals|journal=2D Materials|date=6 August 2014|volume=1|issue=2|pages=021002|doi=10.1088/2053-1583/1/2/021002|arxiv=1407.1219|bibcode=2014TDM.....1b1002G|s2cid=119287785}} It is a direct bandgap material when it is one or two layers (monolayer or bilayer).{{cite journal|last1=Zhang|first1=Lijun|last2=Zunger|first2=Alex|title=Evolution of Electronic Structure as a Function of Layer Thickness in Group-VIB Transition Metal Dichalcogenides: Emergence of Localization Prototypes|journal=Nano Letters|date=11 February 2015|volume=15|issue=2|pages=949–957|doi=10.1021/nl503717p|pmid=25562378|bibcode=2015NanoL..15..949Z}}

The band gap is reduced for tellurium-deficient MoTe2 from 0.97 to 0.5. The work function is 4.1 eV.

=Magnetism=

α–MoTe2 is diamagnetic whereas β–MoTe2 is paramagnetic.

=X-ray=

X-ray photoelectron spectroscopy on clean MoTe2 crystal surfaces show peaks at 231 and 227.8 eV due to molybdenum 3d3/2 and 3d5/2; with 582.9 and 572.5 due to tellurium 3d3/2 and 3d5/2 electrons.

The X-ray K absorption edge occurs at 618.41±0.04 X units compared to molybdenum metal at 618.46 xu.{{cite journal|last1=Bhide|first1=V.G.|last2=Kaicker|first2=S.K.|last3=Bahl|first3=M.K.|title=X-ray K-absorption studies of molybdenum sulphide, selenides and tellurides|journal=Journal of Physics and Chemistry of Solids|date=January 1974|volume=35|issue=8|pages=901–904|doi=10.1016/s0022-3697(74)80096-x|bibcode=1974JPCS...35..901B}}

=Microscopy=

Atomic force microscopy (AFM) of the van der Waals surface of α-MoTe2 shows alternating rows of smooth balls, which are the tellurium atoms. AFM images are often done on a silica (SiO2) surface on silicon. A monolayer of α-MoTe2 has its surface 0.9 nm above the silica, and each extra layer of α-MoTe2 adds 0.7 nm.{{cite journal|last1=Yamamoto|first1=Mahito|last2=Wang|first2=Sheng Tsung|last3=Ni|first3=Meiyan|last4=Lin|first4=Yen-Fu|last5=Li|first5=Song-Lin|last6=Aikawa|first6=Shinya|last7=Jian|first7=Wen-Bin|last8=Ueno|first8=Keiji|last9=Wakabayashi|first9=Katsunori|last10=Tsukagoshi|first10=Kazuhito|title=Strong Enhancement of Raman Scattering from a Bulk-Inactive Vibrational Mode in Few-Layer MoTe|journal=ACS Nano|date=22 April 2014|volume=8|issue=4|pages=3895–3903|doi=10.1021/nn5007607|pmid=24654654|url=http://ir.nctu.edu.tw/bitstream/11536/24246/1/000334990600087.pdf|access-date=11 May 2015}}

Scanning tunneling microscopy (STM) of α-MoTe2 reveals a hexagonal grid like chicken wire, where the molybdenum atoms are contributing to the current. Higher bias voltages are required to get an image, either over 0.5 V or below −0.3 V.{{cite journal|last1=Hla|first1=S.W.|last2=Marinković|first2=V.|last3=Prodan|first3=A.|last4=Muševič|first4=I.|title=STM/AFM investigations of β-MoTe2, α-MoTe2 and WTe2|journal=Surface Science|date=May 1996|volume=352–354|pages=105–111|doi=10.1016/0039-6028(95)01106-4|bibcode=1996SurSc.352..105H}}

β-MoTe2 surfaces examined with scanning tunneling microscopy can show either a pattern of tellurium atoms or a pattern of molybdenum atoms on different parts. When the scanning tip is further from the surface only tellurium atoms are visible. This is explained by the dz2 orbitals from molybdenum penetrating up through the surface layer of tellurium. The molybdenum can supply a much bigger current than tellurium. But at greater distance only the p orbital from tellurium can be detected. Lower voltages than used for α form still produce atomic images.

Friction force microscopy (FFM) has been used to get a slip-stick image at a resolution below that of the unit cell.{{cite journal|last1=Hölscher|first1=H.|last2=Raberg|first2=W.|last3=Schwarz|first3=U. D.|last4=Hasbach|first4=A.|last5=Wandelt|first5=K.|last6=Wiesendanger|first6=R.|title=Imaging of sub-unit-cell structures in the contact mode of the scanning force microscope|journal=Physical Review B|date=15 January 1999|volume=59|issue=3|pages=1661–1664|doi=10.1103/PhysRevB.59.1661|bibcode=1999PhRvB..59.1661H}}{{cite journal|last1=Ishikawa|first1=Makoto|last2=Okita|first2=Shunichi|last3=Minami|first3=Nobuyuki|last4=Miura|first4=Kouji|title=Load dependence of lateral force and energy dissipation at NaF(001) surface|journal=Surface Science|date=January 2000|volume=445|issue=2–3|pages=488–494|doi=10.1016/S0039-6028(99)01115-2|bibcode=2000SurSc.445..488I}}

=Thermal=

Heat in α-MoTe2 is due to vibrations of the atoms. These vibrations can be resolved into phonons in which the atoms move backwards and forwards in different ways. For a monolayer twisting of the tellurium atoms within the plane is termed E″, a scissoring action where tellurium moves in the plane of the layer is termed E′. Where tellurium vibrates in opposite directions perpendicular to the layer out of the plane the phonon mode is A′1 and where the tellurium moves in the same direction opposite to the molybdenum the mode is called A″1. Of these modes the first three are active in the Raman spectrum. In a bilayer there is an extra interaction between the atoms on the bottom of one layer and the atom on the top of the under layer. The mode symbols are modified with a suffix, "g" or "u" . In the bulk form with many layers, the modes are called A1g (corresponding to A′1 in the monolayer), A2u, B1u B2g, E1g, E1u, E2g and E2u. Modes E1g, E12g, E22g, and A1g are Raman active. Modes E11u, E21u, A12u, and A22u are infrared active.

Molar heat of formation of α-MoTe2 is −6 kJ/mol from β-MoTe2. Heat of formation of β-MoTe2 is −84 kJ/mol. For Mo3Te4 it is −185 kJ/mol.{{cite journal|last1=O'Hare|first1=P.A.G.|last2=Hope|first2=G.A.|title=Standard molar enthalpy of formation at 298.15 K of the β-modification of molybdenum ditelluride|journal=The Journal of Chemical Thermodynamics|date=July 1989|volume=21|issue=7|pages=701–707|doi=10.1016/0021-9614(89)90051-7|bibcode=1989JChTh..21..701O }}

Thermal conductivity is 2 Wm−1K−1.

=Pressure=

Under pressure α-MoTe2 is predicted to become a semimetal between 13 and 19 GPa. The crystal form should stay the same at pressures up to 100 GPa.{{cite journal|last1=Rifliková|first1=Michaela|last2=Martoňák|first2=Roman|last3=Tosatti|first3=Erio|title=Pressure-induced gap closing and metallization of MoSe2 and MoTe2|journal=Physical Review B|date=10 July 2014|volume=90|issue=3|pages=035108|doi=10.1103/PhysRevB.90.035108|bibcode=2014PhRvB..90c5108R|arxiv=1605.05111|s2cid=119229787}} β-MoTe2 is not predicted to become more metallic under pressure.

=Angle-resolved photoemission spectroscopy=

MoTe2 exhibits topological Fermi arcs. This is evidence for a new type (type-II) of Weyl fermion that arises due to the breaking of Lorentz invariance, which does not have a counterpart in high-energy physics, which can emerge as topologically protected touching between electron and hole pockets. The topological surface states are confirmed by directly observing the surface states using bulk- and surface-sensitive angle-resolved photoemission spectroscopy.{{cite journal|last1=Deng|first1=Ke|last2=Wan|first2=Guoliang|last3=Deng|first3=Peng|last4=Zhang|first4=Kenan|last5=Ding|first5=Shijie|last6=Wang|first6=Eryin|last7=Yan|first7=Mingzhe|last8=Huang|first8=Huaqing|last9=Zhang|first9=Hongyun|last10=Xu|first10=Zhilin|last11=Denlinger|first11=Jonathan|last12=Fedorov|first12=Alexei|last13=Yang|first13=Haitao|last14=Duan|first14=Wenhui|last15=Yao|first15=Hong|last16=Wu|first16=Yang|last17=Fan|first17=Shoushan|last18=Zhang|first18=Haijun|last19=Chen|first19=Xi|last20=Zhou|first20=Shuyun|title=Experimental observation of topological Fermi arcs in type-II Weyl semimetal MoTe2|journal=Nature Physics|date=5 September 2016|volume=12|issue=12|pages=1105–1110|doi=10.1038/nphys3871|arxiv=1603.08508|bibcode=2016NatPh..12.1105D|s2cid=118474909}}

=Other=

Poisson ratio V=0.37.

Monolayer relaxed ion elastic coefficients C11=80 and C12=21.

Monolayer relaxed ion piezoelectric coefficient d11=9.13.{{cite journal|last1=Balendhran|first1=Sivacarendran|last2=Walia|first2=Sumeet|last3=Nili|first3=Hussein|last4=Ou|first4=Jian Zhen|last5=Zhuiykov|first5=Serge|last6=Kaner|first6=Richard B.|last7=Sriram|first7=Sharath|last8=Bhaskaran|first8=Madhu|last9=Kalantar-zadeh|first9=Kourosh|title=Two-Dimensional Molybdenum Trioxide and Dichalcogenides|journal=Advanced Functional Materials|date=26 August 2013|volume=23|issue=32|pages=3952–3970|doi=10.1002/adfm.201300125|s2cid=95301280 }}

Reactions

=Thermal and degradative processes=

MoTe2 burn with a blue flame, emitting a white smoke of tellurium dioxide.{{cite journal|last1=Shodhan|first1=Ramesh Purushottamdas|title=Solid solubility of sulfur, selenium, and tellurium in molybdenum at 1100°C, lattice constants thermal expansion coefficients, and densities of molybdenum and the molybdenum-base alloys|journal=Masters Theses|url=https://scholarsmine.mst.edu/masters_theses/5332/|access-date=14 May 2015|date=1965}}

MoTe2 dissolves in dilute nitric acid with complete decomposition Hot hydrochloric does not attack MoTe2.{{cite web|last1=Meyer|first1=Shea Silverman|title=Molybdenum ditelluride and high-temperature, high-pressure synthesis method of preparing same|url=https://patents.google.com/patent/US3385667|publisher=US Patent Office|access-date=14 May 2015|date=11 February 1966}}André Morette, Compt. Rend, vol. 215, No. 3, pp. 86–88, (1942) Concentrated sulfuric acid at 261 °C completely dissolves MoTe2. Sodium hydroxide solution also attacks MoTe2.{{cite journal|last1=Obolonchik|first1=V. A.|last2=Vainer|first2=L. S.|last3=Yanaki|first3=A. A.|title=Chemical stability of tellurides of subgroup VIa transition metals in various corrosive media|journal=Soviet Powder Metallurgy and Metal Ceramics|date=September 1972|volume=11|issue=9|pages=727–729|doi=10.1007/BF00801271|s2cid=96325385}}

MoTe2 gradually oxidises in air forming molybdenum dioxide (MoO2). Intermediates may include tellurites Te2MoO7 and TeMo5O16.{{cite journal|last1=Bart|first1=J.C.J.|last2=Cariati|first2=F.|last3=Deiana|first3=S.|last4=Micera|first4=G.|title=The oxidation of molybdenum ditelluride studied by ESR spectroscopy|journal=Inorganica Chimica Acta|date=January 1982|volume=57|pages=95–98|doi=10.1016/s0020-1693(00)86955-8}} Other oxidation products include molybdenum trioxide, tellurium, and tellurium dioxide.{{cite journal|last1=Bart|first1=J. C. J.|last2=Van Truong|first2=Nguyen|last3=Giordano|first3=N.|title=Oxidation of molybdenum ditelluride|journal=Zeitschrift für Anorganische und Allgemeine Chemie|date=November 1980|volume=470|issue=1|pages=233–240|doi=10.1002/zaac.19804700130}}

Flakes of molybdenum ditelluride that contain many defects have lower luminescence, and absorb oxygen from the air, losing their luminescence.{{cite web|last1=Zyga|first1=Lisa|title=Two-dimensional material seems to disappear, but doesn't|url=http://phys.org/news/2015-05-two-dimensional-material-doesnt.html|publisher=PysOrg|access-date=6 May 2015|date=5 May 2015}}{{cite journal|last1=Chen|first1=Bin|last2=Sahin|first2=Hasan|last3=Suslu|first3=Aslihan|last4=Ding|first4=Laura|last5=Bertoni|first5=Mariana I.|last6=Peeters|first6=F. M.|last7=Tongay|first7=Sefaattin|title=Environmental Changes in MoTe2 Excitonic Dynamics by Defects-Activated Molecular Interaction|journal=ACS Nano|date=15 April 2015|pages=5326–5332|doi=10.1021/acsnano.5b00985|pmid=25868985|volume=9|issue=5}}

When heated to high temperatures, tellurium evaporates from molybdenum ditelluride, producing the tellurium-deficient forms and then Mo2Te3.{{Cite journal|last1=Sakanashi|first1=Kohei|last2=Ouchi|first2=Hidemitsu|last3=Kamiya|first3=Kota|last4=Krüger|first4=Peter|last5=Miyamoto|first5=Katsuhiko|last6=Omatsu|first6=Takashige|last7=Ueno|first7=Keiji|last8=Watanabe|first8=Kenji|last9=Taniguchi|first9=Takashi|last10=Bird|first10=Jonathan P|last11=Aoki|first11=Nobuyuki|date=2020-03-04|title=Investigation of laser-induced-metal phase of MoTe2 and its contact property via scanning gate microscopy|url=https://iopscience.iop.org/article/10.1088/1361-6528/ab71b8|journal=Nanotechnology|volume=31|issue=20|pages=205205|doi=10.1088/1361-6528/ab71b8|pmid=32000160|issn=0957-4484|arxiv=2001.07860|bibcode=2020Nanot..31t5205S|s2cid=210859396}} The vapour pressure of Te2 over hot MoTe2 is given by 108.398-11790/T.{{cite journal|last1=O'Hare|first1=P.A.G|title=Inorganic chalcogenides: high-tech materials, low-tech thermodynamics|journal=The Journal of Chemical Thermodynamics|date=July 1987|volume=19|issue=7|pages=675–701|doi=10.1016/0021-9614(87)90090-5|bibcode=1987JChTh..19..675O }} On further heating Mo2Te3 gives off Te2 vapour. The partial pressure of Te2 is given by 105.56-9879/T where T is in K and the pressure is in bars. Molybdenum metal is left behind.

=Epitaxial coating=

The surface on the flat part of the hexagonal crystal (0001) is covered in tellurium and is relatively inert. Layers of tungsten disulfide and tungsten diselenide can be grown on molybdenum ditelluride by van der Waals epitaxy (vdWE).{{cite journal|last1=Tiefenbacher|first1=S.|last2=Pettenkofer|first2=C.|last3=Jaegermann|first3=W.|title=Moiré pattern in LEED obtained by van der Waals epitaxy of lattice mismatched WS2/MoTe2(0001) heterointerfaces|journal=Surface Science|date=April 2000|volume=450|issue=3|pages=181–190|doi=10.1016/s0039-6028(00)00297-1|bibcode=2000SurSc.450..181T}} Gold also can be deposited on the cleavage surfaces of MoTe2. On the α form gold tends to be isotropically deposited, but on the β form it makes elongated strips along the [010] crystal direction.{{cite journal|last1=Hla|first1=S.W.|last2=Marinković|first2=V.|last3=Prodan|first3=A.|title=The growth of gold on (001) surfaces of α- and β-MoTe2|journal=Surface Science|date=June 1996|volume=356|issue=1–3|pages=130–136|doi=10.1016/0039-6028(95)01251-6|bibcode=1996SurSc.356..130H}} Other substances that have been deposited on the crystal surface include indium selenide (InSe),{{cite journal|last1=Schlaf|first1=R.|last2=Tiefenbacher|first2=S.|last3=Lang|first3=O.|last4=Pettenkofer|first4=C.|last5=Jaegermann|first5=W.|title=Van der Waals epitaxy of thin InSe films on MoTe2|journal=Surface Science|date=February 1994|volume=303|issue=1–2|pages=L343–L347|doi=10.1016/0039-6028(94)90610-6|bibcode=1994SurSc.303L.343S}} cadmium sulfide (CdS),{{cite journal|last1=Löher|first1=T.|last2=Tomm|first2=Y.|last3=Pettenkofer|first3=C.|last4=Jaegermann|first4=W.|title=Van der Waals epitaxy of three-dimensional CdS on the two-dimensional layered substrate MoTe2(0001)|journal=Applied Physics Letters|date=1994|volume=65|issue=5|pages=555|doi=10.1063/1.112294|bibcode=1994ApPhL..65..555L}} cadmium telluride (CdTe),{{cite journal|last1=Löher|first1=T.|last2=Tomm|first2=Y.|last3=Klein|first3=A.|last4=Su|first4=D.|last5=Pettenkofer|first5=C.|last6=Jaegermann|first6=W.|title=Highly oriented layers of the three-dimensional semiconductor CdTe on the two-dimensional layered semiconductors MoTe2 and WSe2|journal=Journal of Applied Physics|date=1996|volume=80|issue=10|pages=5718|doi=10.1063/1.363624|bibcode=1996JAP....80.5718L|url=https://tuprints.ulb.tu-darmstadt.de/19923 |doi-access=free}} tin disulfide (SnS2), tin diselenide (SnSe2),{{cite journal|last1=Schlaf|first1=R|last2=Armstrong|first2=N.R|last3=Parkinson|first3=B.A|last4=Pettenkofer|first4=C|last5=Jaegermann|first5=W|title=Van der Waals epitaxy of the layered semiconductors SnSe2 and SnS2: morphology and growth modes|journal=Surface Science|date=August 1997|volume=385|issue=1|pages=1–14|doi=10.1016/S0039-6028(97)00066-6|bibcode=1997SurSc.385....1S}} and tantalum diselenide (TaSe2).{{cite journal|last1=Shimada|first1=Toshihiro|last2=Ohuchi|first2=Fumio S.|last3=Parkinson|first3=Bruce A.|title=Epitaxial Growth and Charge Density Wave of TaSe2|journal=MRS Proceedings|date=15 February 2011|volume=230|doi=10.1557/PROC-230-231}}

=Exfoliation and intercalation=

The sheets in α-MoTe2 can be separated and dispersed in water with a sodium cholate surfactant and sonication. It forms an olive green suspension. MoTe2 is hydrophobic, but the surfactant coats the surface with its lipophilic tail.{{cite book|last1=Chen|first1=Ying (Ian)|title=Nanotubes and Nanosheets: Functionalization and Applications of Boron Nitride and Other Nanomaterials|date=13 February 2015|publisher=CRC Press|page=387|url=https://books.google.com/books?id=u0y3BgAAQBAJ&pg=PA387|isbn=9781466598102}}

The sheets in α-MoTe2 react with lithium to form intercalation compounds. Up to Li1.6MoTe2 can be formed. This material has a similar X-ray diffraction pattern to α-MoTe2.{{cite journal|last1=Ilić|first1=D.|last2=Wiesener|first2=K.|last3=Schneider|first3=W.|last4=Oppermann|first4=H.|last5=Krabbes|first5=G.|title=Cycling behaviour of molybdenum dichalcogenides in aprotic organic electrolyte solution|journal=Journal of Power Sources|date=January 1985|volume=14|issue=1–3|pages=223–229|doi=10.1016/0378-7753(85)88034-4|bibcode=1985JPS....14..223I}} Perylene tetracarboxylic anhydride also intercalates.{{cite book|last1=Salaneck|first1=William R.|title=Conjugated Polymer and Molecular Interfaces: Science and Technology for Photonic and Optoelectronic Application|date=2001|pages=241–267|chapter-url=https://books.google.com/books?id=-kIThT2vdCsC&pg=PA241|chapter=8|publisher=CRC Press |isbn=9780203910870}}{{cite journal|last1=El-Mahalawy|first1=S. H.|last2=Evans|first2=B. L.|title=Temperature dependence of the electrical conductivity and hall coefficient in 2H-MoS2, MoSe2, WSe2, and MoTe2|journal=Physica Status Solidi B|date=1 February 1977|volume=79|issue=2|pages=713–722|doi=10.1002/pssb.2220790238|bibcode=1977PSSBR..79..713E}}

Related Mo-Te phases

Another molybdenum telluride has formula Mo2Te3.

Yet another molybdenum telluride, hexamolybdenum octatelluride Mo6Te8 forms black crystals shaped like cubes. It is formed when the elements in the correct ratio are heated together at 1000 °C for a week. It is related to the Chevrel phases.{{cite journal|last1=Miller|first1=G. J.|last2=Smith|first2=M.|title=Hexamolybdenum Octatelluride, Mo6Te8|journal=Acta Crystallographica Section C|date=15 June 1998|volume=54|issue=6|pages=709–710|doi=10.1107/S0108270197017812|bibcode=1998AcCrC..54..709M |url=https://lib.dr.iastate.edu/chem_pubs/827}} It is not superconducting.{{cite journal|last1=Hamard|first1=C.|last2=Auffret|first2=V.|last3=Peña|first3=O.|last4=Le Floch|first4=M.|last5=Nowak|first5=B.|last6=Wojakowski|first6=A.|title=Chevrel-phase solid solution Mo6Se8−xTex. Study of its superconducting, magnetic and NMR properties|journal=Physica B: Condensed Matter|date=September 2000|volume=291|issue=3–4|pages=339–349|doi=10.1016/S0921-4526(99)02286-3|bibcode=2000PhyB..291..339H}}

Potential applications

Potential uses for MoTe2 include electronics, optoelectronics or a photoelectric cell materials. Diodes have been fabricated from MoTe2 by baking a p-type material in bromine. The diode's current versus voltage plot shows very little current with reverse bias, an exponential region with dV/dln(j) of 1.6, and at higher voltages (>0.3V) a linear response due to resistance. When operated as a capacitor, the capacitance varies as the inverse square of the bias, and also drops for higher frequencies.{{cite journal|last1=Bernède|first1=J. C.|last2=Kettaf|first2=M.|last3=Khelil|first3=A.|last4=Spiesser|first4=M.|title=p-n junctions in molybdenum ditelluride|journal=Physica Status Solidi A|date=16 September 1996|volume=157|issue=1|pages=205–209|doi=10.1002/pssa.2211570126|bibcode=1996PSSAR.157..205B}} Transistors have also been built from MoTe2.{{cite journal|last1=Lin|first1=Yen-Fu|last2=Xu|first2=Yong|last3=Wang|first3=Sheng-Tsung|last4=Li|first4=Song-Lin|last5=Yamamoto|first5=Mahito|last6=Aparecido-Ferreira|first6=Alex|last7=Li|first7=Wenwu|last8=Sun|first8=Huabin|last9=Nakaharai|first9=Shu|last10=Jian|first10=Wen-Bin|last11=Ueno|first11=Keiji|last12=Tsukagoshi|first12=Kazuhito|title=Ambipolar MoTe2 Transistors and Their Applications in Logic Circuits|journal=Advanced Materials|date=May 2014|volume=26|issue=20|pages=3263–3269|doi=10.1002/adma.201305845|pmid=24692079|bibcode=2014AdM....26.3263L |s2cid=12803338 }} MoTe2 has potential to build low power electronics. Field effect transistors (FET) have been built from a bilayer, trilayer and thicker nanolayers.{{cite journal|last1=Pradhan|first1=Nihar R.|title=Field-Effect Transistors Based on Few-Layered α- MoTe2|journal=ACS Nano|volume=8|issue=6|pages=5911–5920|arxiv=1406.0178|doi=10.1021/nn501013c|pmid=24878323|year=2014|bibcode=2014arXiv1406.0178P|s2cid=207709052}} An ambipolar FET has been built, and also a FET that can operate in n- or p-modes which had two top electrodes.{{cite web|last1=Nakaharai|first1=Shu|last2=Yamamoto|first2=Mahito|last3=Ueno|first3=Keiji|last4=Lin|first4=Yen-Fu|last5=Li|first5=Song-Lin|last6=Tsukagoshi|first6=Kazuhito|title=Electrostatic control of polarity of α-MoTe2 transistors with dual top gates|url=https://meetings.aps.org/link/BAPS.2015.MAR.B2.3|publisher=Bulletin of the American Physical Society|access-date=14 May 2015|date=2 March 2015}}

Because MoTe2 has two phases, devices can be constructed that mix the 2H semiconductor, and the 1T' metallic form.

A FET can be constructed with a thin layer of molybdenum ditelluride covered with a liquid gate composed of an ionic liquid or an electrolyte such as potassium perchlorate dissolved in polyethylene glycol. With low gate voltages below 2 volts, the device operates in an electrostatic mode, where the current from drain to source is proportional to the gate voltage. Above 2 volts the device enters an intermediate region where current does not increase. Above 3.5 volts current leaks through the gate, and electrolysis occurs intercalating potassium atoms in the MoTe2 layer. The potassium intercalated molybdenum ditelluride becomes superconducting below 2.8 K.{{cite journal|last1=Shi|first1=Wu|last2=Ye|first2=Jianting|last3=Zhang|first3=Yijin|last4=Suzuki|first4=Ryuji|last5=Yoshida|first5=Masaro|last6=Miyazaki|first6=Jun|last7=Inoue|first7=Naoko|last8=Saito|first8=Yu|last9=Iwasa|first9=Yoshihiro|title=Superconductivity Series in Transition Metal Dichalcogenides by Ionic Gating|journal=Scientific Reports|date=3 August 2015|volume=5|pages=12534|doi=10.1038/srep12534|pmid=26235962|pmc=4522664|bibcode=2015NatSR...512534S}}

As a lubricant molybdenum ditelluride can function well in a vacuum and at temperatures up to 500 °C with a coefficient of friction below 0.1. However molybdenum disulfide has a lower friction, and molybdenum diselenide can function at higher temperatures.{{cite book|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720012801.pdf|pages=161–163|title=Friction, Wear, and Lubrication in Vacuum|year=1971|last1=Buckley|first1=Donald H.|publisher=NASA}}

Related dichalcogenides can be fabricated into fairly efficient photoelectric cells.

Potentially, stacked monolayers of indium nitride and molybdenum ditelluride can result in improved properties for photovoltaics, including lower refractive index, and greater absorbance.{{cite journal|last1=Villegas|first1=Cesar E.P.|last2=Rocha|first2=Alexandre Reily|title=Elucidating the Optical Properties of Novel Hetero-Layered Materials Based on MoTe2-InN for Photovoltaic Applications|journal=The Journal of Physical Chemistry C|date=4 May 2015|pages=150504063713008|doi=10.1021/jp5122596|volume=119|issue=21}}

Cadmium telluride solar cells are often deposited on a backplate of molybdenum. Molybdenum ditelluride can form at the contact, and if this is n-type it will degrade the performance of the solar cell.{{cite journal|last1=Dhar|first1=N.|title=Effect of n-type transition metal dichalcogenide molybdenum telluride (n-MoTe2) in back contact interface of cadmium telluride solar cells from numerical analysis|journal=Chalcogenide Letters|date=June 2014|volume=11|issue=6|pages=271–279|url=https://chalcogen.ro/271_Dhar.pdf|access-date=14 May 2015}}

Small pieces of nanolayers of molybdenum ditelluride can be mixed in and dispersed in molten pewter without reacting, and it causes a doubling of the stiffness of the resultant composite.{{cite journal|last1=May|first1=Peter|last2=Khan|first2=Umar|last3=Coleman|first3=Jonathan N.|title=Reinforcement of metal with liquid-exfoliated inorganic nano-platelets|journal=Applied Physics Letters|date=2013|volume=103|issue=16|pages=163106|doi=10.1063/1.4825279|bibcode=2013ApPhL.103p3106M|url=https://www.tara.tcd.ie/bitstream/2262/67711/1/May%20et%20al%20APL.pdf|hdl=2262/67711|hdl-access=free}}

Molybdenum ditelluride has been used as a substrate for examining proteins with an atomic force microscope. It is superior because the protein sticks harder than with more traditional materials such as mica.{{cite journal|last1=Skorupska|first1=K.|last2=Lewerenz|first2=H.J.|last3=Smith|first3=J.R.|last4=Kulesza|first4=P.J.|last5=Mernagh|first5=D.|last6=Campbell|first6=S.A.|title=Macromolecule–semiconductor interfaces: From enzyme immobilization to photoelectrocatalytical applications|journal=Journal of Electroanalytical Chemistry|date=November 2011|volume=662|issue=1|pages=169–183|doi=10.1016/j.jelechem.2011.05.020}}

β–MoTe2 is a comparatively good hydrogen evolution electrocatalyst showing even in unsupported form and without any additional nanostructuring a Tafel slope of 78 mV/dec. The semiconducting polymorph of α–MoTe2 was found inactive for HER. The superior activity was attributed to higher conductivity of β–MoTe2 phase.{{cite journal |last1=McGlynn|first1=Jessica C.|last2=Cascallana-Matias|first2=Irene|last3=Fraser|first3=James P.|last4=Roger|first4=Isolda|last5=McAllister|first5=James|last6=Miras|first6=Haralampos N.|last7=Symes|first7=Mark D.|last8=Ganin|first8=Alexey Y.|title=Molybdenum Ditelluride (MoTe2) Rendered into an Efficient and Stable Electrocatalyst for the Hydrogen Evolution Reaction by Polymorphic Control|journal=Energy Technology|date=July 2017|volume=5|issue=2|pages=345–350|doi=10.1002/ente.201700489|url=https://eprints.gla.ac.uk/144469/13/144469.pdf|doi-access=free}}

Recent work has shown that electrodes covered with β–MoTe2 demonstrated an increase in the amount of hydrogen gas produced during the electrolysis when a specific pattern of high-current pulses was applied. By optimising the pulses of current through the acidic electrolyte, the authors could reduce the overpotential needed for hydrogen evolution by nearly 50% when compared with the original non-activated material.{{Cite journal|last1=McGlynn|first1=Jessica C.|last2=Dankwort|first2=Torben|last3=Kienle|first3=Lorenz|last4=Bandeira|first4=Nuno A. G.|last5=Fraser|first5=James P.|last6=Gibson|first6=Emma K.|last7=Cascallana-Matías|first7=Irene|last8=Kamarás|first8=Katalin|last9=Symes|first9=Mark D.|last10=Miras|first10=Harry N.|last11=Ganin|first11=Alexey Y.|date=2019-10-29|title=The rapid electrochemical activation of MoTe 2 for the hydrogen evolution reaction|journal=Nature Communications|language=en|volume=10|issue=1|pages=4916|doi=10.1038/s41467-019-12831-0|pmid=31664018|pmc=6820771|issn=2041-1723|bibcode=2019NatCo..10.4916M}}

Few-layered metallic form 1T'-MoTe2 (β–MoTe2) enhance SERS signal and therefore, some lipophilic markers (β–sitosterol) of coronary artery and cardiovascular diseases can be selectively detected at the surface of the few-layered films.{{Cite journal|last1=Fraser|first1=James P.|last2=Postnikov|first2=Pavel|last3=Miliutina|first3=Elena|last4=Kolska|first4=Zdenka|last5=Valiev|first5=Rashid|last6=Švorčík|first6=Vaclav|last7=Lyutakov|first7=Oleksiy|last8=Ganin|first8=Alexey Y.|last9=Guselnikova|first9=Olga|date=2020-09-28|title=Application of a 2D Molybdenum Telluride in SERS Detection of Biorelevant Molecules|journal=ACS Applied Materials & Interfaces|volume=12|issue=42|pages=47774–47783|doi=10.1021/acsami.0c11231|pmid=32985181|issn=1944-8244|doi-access=free}}

References

{{Reflist|30em}}

{{Commons category|Molybdenum ditelluride}}

{{Molybdenum compounds}}

{{Tellurides}}

Category:Molybdenum(IV) compounds

Category:Tellurides

Category:Transition metal dichalcogenides

Category:Monolayers