Improved optical absorption and photocurrent of GaAs solar cells with hexagonal micro-hole array surface texturing

Abstract

We demonstrate an improvement in power conversion efficiency of single-junction GaAs solar cells incorporated with micro-hole arrays. The GaAs solar cells are grown by low-pressure metalorganic chemical vapor deposition on (100) GaAs substrates. The micro-hole arrays were formed on the surface of the GaAs solar cells, and the measurement on the reflectance and photocurrent generation are performed using an UV–Vis–NIR spectrometer and an external quantum efficiency measurement system, respectively. It is shown that the micro-hole arrays have the effect of scattering the incident light away from the original direction resulting in the reduction of reflectance over 350–873nm spectrum regime. The micro-hole arrays formed on the surface of the solar cells enhanced the photocurrent generation which was increased with the extended optical path length in the absorption layer. As a result, an enhancement in power conversion efficiency of up to 12.3% compared to that of reference solar cell was obtained under 1sun AM 1.5G illumination at room temperature.