Nitride-based light-emitting solar cell

We report on the characteristics of a group-III-nitride-based solar cell. A GaInN/GaN double heterojunction p-i-n solar cell composed of a GaInN active layer sandwiched between n-type and p-type GaN layers was grown by metal-organic vapor phase epitaxy through an undoped GaN layer on (0001) sapphire substrate. The InN molar fraction of the GaInN active layer was determined to be 11% from a secondary ion mass spectrometry profile. The maximum external quantum efficiency reached 65%, and the internal quantum efficiency was 95% or more. This device emitted light after forward current injection. The PL peak almost corresponded to the absorption edge. However, the electroluminescence (EL) peak was at the wavelength much longer than the absorption edge. The open-circuit voltage is 1.51 V, the fill factor is 52%, and the short-circuit current density is 1.6 mA/cm(2). (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim