Improvement of Cu(In,Ga)Se2 photovoltaic performance by adding Cu-poor compounds Cu(In,Ga)_3Se_5 at Cu(In,Ga)Se2/CdS interface

摘要

We report on the improvement of Cu(In,Ga)Se2 (CIGS) photovoltaic performance by inserting Cu-poor compounds Cu(In,Ga)_3Se_5 at CIGS/CdS interface. It was experimentally found that formation of the Cu(In,Ga)_3Se_5 layer at the CdS/CIGS interface was quite important to boost the photovoltaic performance. Cd diffusion was promoted by introducing the layer, and conductivity type turned to n-type near the surface. As a result, cell performance was improved owing to suppression of recombination at the interface by stronger band-bending. Additionally, it was shown that the interval time before the growth of the Cu(In,Ga)_3Se_5 layer is important to eliminate the Cu intermixing in CIGS.