Date

Place

[P2-137]
14:00 ~ 15:30
Title:Effects of Annealing Process on CZTS Thin-Film Solar Cell
Kee-Jeong Yang and Jun-Hyoung Sim (DGIST, Korea)
Abstract: CZTS-based solar cells represent a significant improvement because of a useful band-gap energy and a high absorption coefficient. In this study, we investigated annealing effects of device on CZTS solar cell characteristics. We verified that the solar cell characteristics improve in direct proportion to the Na concentration in a Mo layer. The Na concentration in the Mo layer increased in proportion to the increase in Mo-layer annealing temperature. As the Mo-layer annealing temperature increased, the voltage shortfall decreased. This indicates that the concentration of recombination centers in the absorber layer was reduced. Also we verified that the solar cell characteristics decline in direct proportion to the Na concentration in a buffer layer. Sample was annealed to control the Na concentration in a buffer layer. After CZTS absorber layer sulfurization process, Na is accumulated near the absorber layer surface. When a buffer layer was deposited on the absorber layer, Na near the absorber layer surface is diffused into a buffer layer. As the minority carrier mobility decreases, device series resistance increases. So Na concentration in a buffer layer must be reduced.
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