Numerical optimization of absorber and buffer layers of CZTS thin film solar cells

In this paper, the performance of Cu
2
ZnSnS
4
(CZTS) thin film solar cell has been analysed numerically using SCAPS-1D. Firstly, the thickness, carrier density and defect density of CZTS absorber layer and then the thickness and carrier density of CdS buffer layer was varied to observe their effect on the cell performance. From the simulated results, the optimal thickness of 3000 nm, carrier density of 10
¹⁶
cm
⁻³
and defect density of 10
¹⁵
cm
⁻³
was obtained for CZTS. For CdS, optimal thickness of 60 nm and carrier density of 10
¹⁷
cm
⁻³
was obtained. Thus, the solar cell efficiency of 21.79% and fill factor of 68.79% (with VOC of 1.0017 V and JSC of 31.624 mAcm
⁻²
) has been achieved at 300 K. Finally, the effect of operating temperature on the cell performance showed that increased temperature would affect the efficiency in order of −0.25%/°C.