摘要
Cd1-xZnxS/Cu2ZnSnS4 （CZTS）-based thin film solar cells usually use CdS as a buffer layer, but due to its smaller band gap （2.4 eV）, CdS film has been replaced with higher band gap materials. The cadmium zinc sulfide （CdZnS） ternary compound has a higher band gap than other compounds, which leads to a decrease in window absorption loss. In this paper, the band offsets at Cd1-xZnxS/CuzZnSnS4 （CZTS） heterointerface are calculated by the first-principles, density- functional and pseudopotential method. The band offsets at Cdl xZnxS/CZTS heterointerface are tuned by controlling the composition of Zn in Cd1-xZnxS alloy, the calculated valence band offsets are small, which is consistent with the commonanion rule. The favorable heterointerface of type-I with a moderate barrier height （〈 0.3 eV） can be obtained by controlling the composition of Zn in Cdl-xZnxS alloy between 0.25 and 0.375.
Cd1-xZnxS/Cu2ZnSnS4 （CZTS）-based thin film solar cells usually use CdS as a buffer layer, but due to its smaller band gap （2.4 eV）, CdS film has been replaced with higher band gap materials. The cadmium zinc sulfide （CdZnS） ternary compound has a higher band gap than other compounds, which leads to a decrease in window absorption loss. In this paper, the band offsets at Cd1-xZnxS/CuzZnSnS4 （CZTS） heterointerface are calculated by the first-principles, density- functional and pseudopotential method. The band offsets at Cdl xZnxS/CZTS heterointerface are tuned by controlling the composition of Zn in Cd1-xZnxS alloy, the calculated valence band offsets are small, which is consistent with the commonanion rule. The favorable heterointerface of type-I with a moderate barrier height （〈 0.3 eV） can be obtained by controlling the composition of Zn in Cdl-xZnxS alloy between 0.25 and 0.375.
基金
Project supported by the Special Funds of the National Natural Science Foundation of China(Grant Nos.11547226 and 11547180)
