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Field‐Dependent Electrical and Thermal Transport in Polycrystalline WSe 2
Author(s) -
Kim WungYeon,
Kim HyunJeong,
Hallam Toby,
McEvoy Niall,
Gatensby Riley,
Nerl Hannah C.,
O'Neill Katie,
Siris Rita,
Kim GyuTae,
Duesberg Georg S.
Publication year - 2018
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201701161
Subject(s) - materials science , thermoelectric effect , seebeck coefficient , thermoelectric materials , fabrication , optoelectronics , crystallite , lithography , nanotechnology , field effect transistor , transistor , thermal conductivity , composite material , electrical engineering , metallurgy , medicine , physics , alternative medicine , pathology , voltage , thermodynamics , engineering
Owing to their desirable electrical and thermoelectric properties, transition metal dichalcogenides (TMDs) have attracted significant attention. It is important to develop an easy synthetic method and a simple device fabrication process for TMDs. In this study, WSe 2 films were synthesized on a large scale by thermally assisted conversion (TAC) of W films on SiO 2 /Si substrates at 600 °C. The TAC process yields homogeneous polycrystalline films of controlled thickness over large areas which have the advantage that they can be adapted for mass production for applications in electronics and thermoelectrics. In this regard, pre‐patterning of the deposited metal films allows for devices to be easily fabricated without any etch process. UV‐lithography‐defined W structures have been deposited and after conversion to WSe 2 their electrical and thermoelectric properties have been studied. Using e‐beam lithography, a field effect transistor (FET) with a WSe 2 channel was fabricated. This showed p‐type behavior and reasonable field effect mobility value. The thermoelectric properties of WSe 2 thin films were analyzed by additionally integrating micro heating elements to the WSe 2 FET. The maximum Seebeck coefficient and power factor ( S 2 ·σ) values were calculated to be ≈61 mV·K −1 ( V g = 45 V) and ≈1.3 nW·K −2 ·cm −1 , respectively.