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Thermoelectric Properties of Substoichiometric Electron Beam Patterned Bismuth Sulfide
journal contribution
posted on 2020-07-20, 21:09 authored by Jose Recatala-Gomez, Hong Kuan Ng, Pawan Kumar, Ady Suwardi, Minrui Zheng, Mohamed Asbahi, Sudhiranjan Tripathy, Iris Nandhakumar, Mohammad S. M. Saifullah, Kedar HippalgaonkarDirect
patterning of thermoelectric metal chalcogenides can be
challenging and is normally constrained to certain geometries and
sizes. Here we report the synthesis, characterization, and direct
writing of sub-10 nm wide bismuth sulfide (Bi2S3) using a single-source, spin-coatable, and electron-beam-sensitive
bismuth(III) ethylxanthate precursor. In order to increase the intrinsically
low carrier concentration of pristine Bi2S3,
we developed a self-doping methodology in which sulfur vacancies are
manipulated by tuning the temperature during vacuum annealing, to
produce an electron-rich thermoelectric material. We report a room-temperature
electrical conductivity of 6 S m–1 and a Seebeck
coefficient of −21.41 μV K–1 for a
directly patterned, substoichiometric Bi2S3 thin
film. We expect that our demonstration of directly writable thermoelectric
films, with further optimization of structure and morphology, can
be useful for on-chip applications.