| 초록 |
We report the effects of both sulfur source and H2S gas concentration on the properties of Cu2ZnSnS4 (CZTS) thin films directly synthesized on Mo/glass substrates by using chemical bath deposition method. Sodium thiosulfate pentahydrate (hypo), thiourea, thioacetamide were used as sulfur sources. Especially, we studied the effects of sulfur source concentrations among thiosulfate, thiourea, and thioacetamide based on morphology and thickness of as grown CZTS film. We studied the effects of thiosulfate concentration on the sulfurized CZTS film morphology and photoelectrical properties. Smooth CZTS films were grown on substrates at am optimized CBD condition. CZTS films sulfurized at low H2S concentrations of 0.05 and 0.1 % showed a very rough and porous film morphology whereas that sulfurized at 5 % H2S yielded a very smooth and dense film morphology. CZTS films for higher thiosulfate concentrations (1 M, 2M) seemed to be fully crystallized in the form of kesterite crystal when films were sulfurized at 500 oC for 2 h. The kesterite CZTS film showed reasonably good photocurrent response upon illumination of light. The room-temperature photoluminescence spectrum peaked at approximately 1.4 – 1.5 eV, consistent with an optimal bandgap for CZTS solar cell applications. |
