AlGaInP/GaP Heterostructures Bonded with Si Substrate to Serve as Solar Cells and Light Emitting Diodes

In this study, an AlGaInP/GaP-based heterostructure featuring a silicon substrate and a SiO 2 /indium tin oxide/Ag omnidirectional reflector, using a metal-to-metal bonding technique, serves as a dual-function device operating in light emitting and photovoltaic modes. To enhance the light extraction efficiency and conversion efficiency, AlGaInP/Si heterojunction devices with a periodic texture applied to the n-(Al 0.5 Ga 0.5 ) 0.5 In 0.5 P surface layer using photolithography and a wet etching process are also presented. Using the light emitting mode and a 350 mA current injection, the external quantum efficiencies of AlGaInP/Si light emitting diodes (LEDs) with (LED-I) and without (LED-II) a textured surface are measured at approximately 17.3 and 11.8%, respectively. The enhancement of the output power in LED-I can be attributed to a multitude of bowl-shaped notches on the surface, resulting in a reduction in the reabsorption probability of photons inside the device because the photon path length of LED-I is shorter than LED-II before photons escape into free space. When devices are operated in a photovoltaic mode, measured under an air mass 1.5 condition, the typical efficiency and fill factor are around 4.67 and 83%, respectively, for devices with a textured surface.