| 초록 |
Earth abundant, cost-efficient and environmental friendly kesterite Cu2ZnSnS4 (CZTS), Cu2ZnSnSe4 (CZTSe), and Cu2ZnSn(S,Se)4 (CZTSSe) materials are being extensively studied for the application of thin-film solar cells (TFSCs). Although CdS has been the most widely popular n-type buffer layer used in the TFSC fabrication, however, its prospect is limited by its toxic nature and parasitic loss in the short wavelength range. Recently, Cd-free non-toxic Zn(O,S) has emerged as promising buffer layers for solar cell applications. In the present work, the performance of CZTSSe-based solar cells fabricated with atomic layer deposited (ALD) Zn(O,S) buffer layers has been investigated. The growth parameters of ALD-Zn(O,S) were optimized by varying the substrate temperature and O/O+S ratio. The highest cell efficiency of 8.99% (Voc = 458 mV, Jsc = 36.85 mA/cm2, and FF = 0.53) was obtained at a growth temperature of 90 ºC with an O/(O+S) ratio of 0.9. The reference device fabricated with conventional chemical bath deposited CdS buffer layer displayed relatively higher cell efficiency of 9.26%. This study demonstrates that using alternative ALD-grown Zn(O,S) buffer layer more than 90% of the standard CdS-based cell efficiency can be achieved. |
