Improvement in the performance of CIGS solar cells by introducing GaN nanowires on the absorber layer

Cu(In, Ga) Se₂ (CIGS) thin-film solar cells are currently the fastest growing photovoltaic technology due to the higher performance ratio and lower energy payback time compared to the silicon, and good stability. Despite of these interesting properties, CIGS solar cells suffer from poor spectral response at short wavelengths particularly in the range of 300–400 nm. In the present work, we have introduced GaN nanowires in CIGS solar cells in order to improve the performance of photovoltaic device in the short wavelength region (300–400 nm). To evaluate the influence of GaN nanowires, the morphological, structural and electrical properties have been studied. These studies have shown the introduction of GaN nanowires not only improve the cell efficiency but also enhance the spectral response in the wavelength range 300–400 nm. The CIGS solar cells fabricated with GaN nanowires displayed power conversion efficiency of 10.15% with a fill factor of 65%, which are substantially higher than that of reference cell (without GaN nanowires).