LAUSR

Direct 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, sub-stoichiometric 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.