[1] Han R, Liu Z, Dong Q. Study of CIGS absorber thickness and gradient bandgap effect on device performance[C], 1-3(2021).

[2] Diaz R, Merino J M, Leon M et al. Effect of stoichiometric deviations on the structural properties of CuInSe₂， CuIn_0.5Ga_0.5Se₂ and CuGaSe₂[J]. Japanese Journal of Applied Physics, 39, 339(2000).

[3] Kamikawa Y, Nishinaga J, Shibata H et al. Efficient narrow band gap Cu （In， Ga） Se₂ solar cells with flat surface[J]. ACS Applied Materials and Interfaces, 12, 45485-45492(2020).

[4] Monsefi M, Kuo D H. Influence of Cu content on the n - p transition of 15% Sn-doped Cu_x （In， Ga） Se₂ bulk materials[J]. Journal of Alloys and Compounds, 580, 348-353(2013).

[5] Zhao Y, Yuan S, Chang Q et al. Controllable formation of ordered vacancy compound for high efficiency solution processed Cu （In， Ga） Se₂ solar cells[J]. Advanced Functional Materials, 31, 2007928(2021).

[6] Siebentritt S, Gutay L, Regesch D et al. Why do we make Cu （In， Ga） Se₂ solar cells non-stoichiometric？[J]. Solar Energy Materials and Solar Cells, 119, 18-25(2013).

[8] Sun L, Ma J H, Yao N J et al. Influence of various Cu contents on the microstructure of Cu （In， Ga） Se₂ thin films[J]. Journal of Infrared and Millimeter Waves, 36, 1-6(2017).

[9] Pan D, An L, Sun Z et al. Synthesis of Cu‑In‑S ternary nanocrystals with tunable structure and composition[J]. Journal of the American Chemical Society, 130, 5620-5621(2008).

[10] Çetinkaya S. Study of electrical effect of transition-metal dichalcogenide-MoS₂ layer on the performance characteristic of Cu₂ZnSnS₄ based solar cells using wxAMPS[J]. Optik, 181, 627-638(2019).

[12] Fonash S[M]. Solar cell device physics(2012).

[13] Et-taya L, Oudlimane T, Benami A. Numerical analysis of earth-abundant Cu₂ZnSn （S_xSe_1-x）₄ solar cells based on Spectroscopic Ellipsometry results by using SCAPS-1D[J]. Solar Energy, 201, 827-835(2020).

[14] Uhl A R, Katahara J K, Hillhouse H W. Molecular-ink route to 13.0% efficient low-bandgap CuIn （S， Se）₂ and 14.7% efficient Cu （In， Ga）（S， Se）₂ solar cells[J]. Energy and Environmental Science, 9, 130-134(2016).