Research Information System
International journal of energy studies (Online), vol.8, no.4, pp.849-858, 2023 (TRDizin)
In this study, the impact of tellurium addition on
the microstructure of the copper indium gallium selenide absorber layer with a
copper-poor stoichiometry and the photovoltaic properties of
SLG/Mo/CIGS/CdS/ZnO/ITO/Ni-Al-Ni solar cells was investigated. Absorber layer,
CdS buffer, ZnO and ITO layers, and the Ni-Al-Ni front contact were produced
using three-stage co-evaporation, chemical bath deposition, RF magnetron
sputtering, and e-beam evaporation techniques, respectively. The thickness and
the composition of the absorber layer were controlled in situ. NaF post
deposition treatment were applied to the absorber layer. The addition of
tellurium improved the crystal quality by increasing the average grain size and
decreased the surface roughness. Decreasing surface roughness increased
reflection and thus decreased the amount of sunlight absorbed, which in turn
reduced current collection. Open-circuit voltage was effected by impurity level
and the grain boundry recombination. While moderate tellurium addition reduced
grain boundary recombination, excessive tellurium addition created stress,
caused crack formation, and increased recombination by reducing crystal
quality. The optimum tellurium amount in the copper-poor CIGS structure was
found to be 1.1 atomic percent. The control of the microstructure of the
absorber and the efficiency improvement of the solar cell were achieved
successfully.