Study of Electrical Characteristics of GaN-Based Photovoltaics With Graded In$_{x}$ Ga$_{1-{x}}$ N Absorption Layer

GaN-based photovoltaics (PVs) with a graded In
_x
Ga
_1-x
N absorption layer (GIAL) were investigated. Compared to PVs with a single InGaN absorption layer (SIAL), the leakage current and carrier transportation could be improved in the PVs with a GIAL, which was attributed to the reduction of lattice mismatch and improvement of band offset, respectively. Under AM 1.5G one-sun illumination, the open-circuit voltage and short-circuit current density of the PVs with a GIAL were 1.33 V and 5.9 × 10
^-4
A/cm
²
, respectively, while the fill factor and power conversion efficiency were 65% and 0.51%, respectively. The efficiency of PVs with a GIAL is much higher than that of PVs with a SIAL.