Investigation of Gallium Nitride Emitter Thickness in GaN/Si Heterojunction Solar Cell by SCAPS-1D

III-nitride materials have attracted wide interests for optoelectronic and electronic applications due to their unique and tuneable semiconducting and optical properties. Gallium nitride (GaN) exhibits wide bandgap of 3.42[Formula: see text]eV, high thermal and chemical stability, with a strong potential to act as an electron selective contact (i.e., emitter) in GaN/Si heterojunction solar cells. However, despite all the advantages, to date, there is no published research that has which utilized GaN as an emitter in the GaN/Si heterojunction solar cells. In this work, SCAPS-1D simulation is utilized to investigate the electrical properties of GaN emitter on 150[Formula: see text][Formula: see text]m-thick monocrystalline silicon (mono c-Si) absorber layer in GaN/Si heterojunction solar cell architecture. GaN emitter with the thickness of 30–120[Formula: see text]nm are studied and the effects toward open-circuit voltage ([Formula: see text]), short-circuit current density ([Formula: see text], fill factor (FF), power conversion efficiency (PCE) and external quantum efficiency (EQE) of the solar cell are analyzed. The optimum thickness of the GaN emitter is found to be 60[Formula: see text]nm with [Formula: see text] of 37.53[Formula: see text]mA/cm 2 , [Formula: see text] of 628.73[Formula: see text]mV and PCE of 19.43%. The findings show the potential of the GaN/Si heterojunction solar cell for the future of the PV industry, especially for applications in harsh and extreme conditions.