Improved performance of InGaN/GaN multilayer solar cells with an atomic-layer-deposited Al2O3 passivation film

The surface passivation for InGaN/GaN multilayer solar cells was investigated, and it was confirmed that the device with an atomic-layer-deposited (ALD) Al2O3 passivation film showed high internal and external quantum efficiencies of 99 and 84%, respectively, along with a high energy conversion efficiency of 1.31% under a 1-sun air-mass 1.5 global illumination. The current−voltage characteristics indicated that the ALD Al2O3 film improved the surface electrical stability. The carrier lifetime measurements revealed that the ALD Al2O3 film reduced the surface carrier recombination rate and thereby contributed to the improvement of the solar cell performance in a short wavelength region.