Grain Growth in Cu₂ZnSnS₄Thin Films Using Sn Vapor Transport for Photovoltaic Applications

Abstract

Cu2ZnSnS4 thin films containing grains grown using Sn vapor transport (TVT) were investigated. Structural characterization revealed that the grain sizes were equal to or larger than the film thickness (1–4 µm) and significantly larger than those in the case of growth without TVT (60 nm). Furthermore, no phase separation was detected. Photothermal diffraction spectroscopy revealed that the optical absorption coefficient was very low in the subgap region, 7×101 cm-1, suggesting the suppression of defect formation. Finally, a TVT-processed thin film was used as an absorber in a solar cell, and a conversion efficiency of 6.9% was achieved.

Annealing temperature dependence of photovoltaic properties of solar cells containing Cu2SnS3 thin films produced by co‐evaporation

“…Excess Sn sublimates from Sn‐rich CTS films in the form of SnS at high temperatures , and the amount of sublimation increases with temperature. Since for a similar sulfide compound, Cu 2 ZnSnS 4 , crystal growth has been reported to occur in a SnS atmosphere , it is expected that the sublimated SnS will promote crystal growth of CTS. The grain size is, therefore, expected to increase with annealing temperature.…”

Point defects, compositional fluctuations, and secondary phases in non-stoichiometric kesterites

“…Interestingly, a CZTS layer grown in a sequential process featured homogeneously distributed ZnS segregations [130], indicating that the presence and distribution of secondary phases depends on both the integral sample composition and the deposition process. The sensitivity of XANES to the presence of secondary phases was also used to exclude the occurrence of binary segregations and thus to confirm the single-phase nature of different CZTS thin films [131], nanocrystals [132], and powder [133].…”

Impact of alloying duration of an electrodeposited Cu/Sn/Zn metallic stack on properties of Cu2ZnSnS4 absorbers for thin‐film solar cells

“…Approaches for preparation of CZTS and CZTSSe thin films can be roughly divided into vacuum and non-vacuum processes. Vacuum deposition processes, including sputtering [2][3][4][5][6][7][8] and evaporation [9][10][11], always require complex equipment and are consequently costly to implement on a large scale. In contrast, non-vacuum solution-based processes, such as solution coating [12,13], nano particle ink coating [14][15][16][17], hydrazine solution coating [18][19][20][21][22][23][24], and electrodeposition [25][26][27][28][29][30][31][32][33][34][35], potentially provide low-cost scalable routes to prepare CZTS-and CZTSSe-based solar devices.…”