A simple and efficient device configuration applicable in high-performance solar cells with limited material requirements

Abstract

Efficient device configurations with simple structure and limited requirements for active materials, including quality and quantity, are of particular interest in solar cells. In this paper, a ‘U’ pool-shaped nanowall array is proposed and investigated regarding light management and photoelectric conversion behaviors based on gallium arsenide (GaAs). It was found that excellent omnidirectional light trapping can be realized in a broad structural parameter range. A photocurrent density (Jph) up to ~29.0 mA cm−2, i.e. ~93.5% absorption of incident photons with energy larger than 1.42 eV, i.e. the bandgap energy of GaAs is predicted at AM 1.5G illumination for the optimized array with an effective thickness of less than 350 nm. As a distinct comparison, a 2000 nm thick flat GaAs film only delivers Jph of ~19.8 mA cm−2 under the same illumination. Photoelectric simulations predict that to achieve a rationally high power conversion efficiency, bulk lifetime longer than 10−7 s for minority carriers in the base material, appropriate surface passivation of reducing the recombination velocity to the order of ~102 cm s−1 and contact resistance between electrodes and emitters lower than 10 Ω cm2 are required.