EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Tin sulfides thin films (SnS, SnS2 and Sn2S3) are promising candidates for low-cost photovoltaic technologies based on non-toxic and earth-abundant elements. [1, 2] The tin sulfide thin films can be prepared by various approaches such as chemical vapor deposition (CVD) [3] atomic layer deposition (ALD) [4], or sulfurization of a pre-deposited tin oxide layer [5]. In general, elemental sulfur (S8) and hydrogen sulfide (H2S) are used as sulfur sources. However, the processes with solid precursors or toxic gas are not well suited to industrial production owing to security and reproducibility issues. In this context, volatile organosulfur compounds represent a serious alternative for both H2S and elemental sulfur. In the present study, tin sulfide thin films are prepared by low-temperature sulfurization of ALD-deposited SnO2 thin films using different organosulfur compounds. Sulfurization kinetics were investigated. The sulfurized SnO2 thin films were examined by various characterization techniques (Raman spectroscopy, x-ray diffraction, x-ray fluorescence, etc.) to access the physical and chemical properties. This study pointed out the ability of selected organosulfur molecules to convert amorphous SnO2 into polycrystalline SnS or SnS2 phases below 400 °C. The conversion of SnS into SnS2 was also demonstrated, thus opening the way towards the formation of p-SnS/n-SnS2 heterojunctions. In contrast, another organosulfur molecule has demonstrated its ability to etch SnO2 at temperatures as low as 200 °C. The different reactivity of organosulfur molecule
will be discussed further.

References
[1] Whittles T.J. Electronic Characterisation of Earth-Abundant Sulphides for Solar Photovoltaics. Springer, Cham, Switzerland, 2018, 175-208.
[2] Guc et al. Acta Mater. 2020, 183, 1-10.
[3] Delabie et al. J. Mater. Chem. C, 2018, 6, 6172-6178.
[4] Kim et al. Sci. Rep., 2019, 9, 10225.
[5] Kim et al. Nanoscale, 2018, 10, 17712-17721.