P-GaN/i-In $$_\mathrm{x }$$ x Ga1 $$_\mathrm{x }$$ x N/n-GaN solar cell with indium compositional grading

Abstract

The effect of indium compositional grading on the performance of $$\hbox {p-GaN/i}\hbox {-}\hbox {In}_\mathrm{x}\hbox {Ga}_{1-\mathrm{x}}\hbox {N/GaN}$$ solar cell has been investigated using TCAD Silvaco. An enhancement in efficiency of almost two times is found and this may be due to the increase in short circuit current density and open circuit voltage. This can be imputed to high carrier collection due to the reduction of band offset at the interface and high band bending in intrinsic layer. The optimized $$\hbox {GaN}/\hbox {In}_\mathrm{x}\hbox {Ga}_{1-\mathrm{x}}\hbox {N}$$ solar cell with indium composition grading from 0 to 0.11, results fill factor of 77 %, short circuit current density of 0.99 mA/cm $$^{2}$$ and open circuit voltage of 2.21 V under AM1.5G illumination.