The major influence of the conduction-band-offset on Zn(O, S)/CuIn0.7Ga0.3Se2 solar cells

In this study, we simulated this kind of CIGS thin-film solar cell with the variation of Zn(O, S) affinity until an optimal interval which corresponds to the best efficiency of 20.63% where the affinity of CIGS remains constant. Its optimal value is around 4.58 eV for a (gallium/indium) ratio of 0.3 eV corresponds to a band gap energy of 1.17 eV as it is already demonstrated by several groups (Repins et al., 2008, Powalla et al., 2009) and the resulting Conduction Band Offsets (CBO) between CIGS and Zn(O, S) can range from −0.2 to +1.2 eV if the full range of the (oxygen/sulfur) ratio is considered from the pure ZnO to the pure ZnS.The simulation tool used for this study is Atlas of Silvaco-package based on the digital resolution 2D transport equations governing the conduction mechanisms in semiconductor devices as described in Section “Atlas numerical model description”. The J-V characteristics are simulated under standard AM1.5G Illumination.

Source: Results in Physics - July 23, 2018 Category: Physics Source Type: research