Improved Power Conversion Efficiency of InGaN Photovoltaic Devices Grown on Patterned Sapphire Substrates

The InGaN/sapphire-based photovoltaic (PV) cells with Al
_0.14
Ga
_0.86
N/In
_0.21
Ga
_0.79
N superlattice structures that serve as absorption layers were grown on patterned sapphire substrates (PSSs). Under global air-mass 1.5 conditions, the short-circuit current density, the open-circuit voltage, and the fill factor obtained from the PV cells were 1.21 mA/cm
²
, 2.18 V, and 0.65, respectively, corresponding to a conversion efficiency of 1.71%. Compared with PV devices grown on flat sapphire substrates, the photocurrent of PSS-grown PV devices was enhanced by 26%. The improved PV performance was attributable to the positive effects of the PSS on the material quality.