Efficiency improvement of short-period InGaN/GaN multiple-quantum well solar cells with H₂ in the GaN cap layer

The thick-well InGaN/GaN short period multiple quantum well solar cells (SCs) with H₂ in the GaN cap layer exhibits an improved open-circuit voltage, fill factor, and conversion efficiency η compared with those of SCs without the ramped H₂ in the GaN cap layer. The η of the SC with the ramped H₂ in the GaN cap layer (0.77%) shows a 67.4% improvement compared with that of the SC without the ramped H₂ (0.46%). Furthermore, the η of SC with patterned sapphire substrate (PSS) (1.36%) indicates a 76.6% improvement compared with that of SC without PSS (0.77%).