NUMERICAL SIMULATION OF MULTI-QUANTUM WELL SOLAR CELLS GAAS / ALGAAS

Abstract

Inserting Multi-quantum well into solar cells proved to be a promising technique for producing high efficiency third generation solar cells. The presence of quantum well increases the absorption spectra into longer wavelengths, therefore increasing the short-circuit current density while maintaining the open-circuit voltage at acceptable level [2;3]. In this work;we evaluate the generated photocurrent in an AlxGa1-xAs/GaAs p-i-n solar cell using a simple approach. Firstly Schrödinger equation is solved numerically to determine the confined energy states in a single quantum well; the second step consists of calculating the absorption coefficient α ( λ ) taking into account the allowed valence to conduction bands transitions. Finally the total photocurrent is analysed for various structure parameters specifically; width, height (related to the Aluminum concentration x ), and number of wells inside the intrinsic layer. The simulated results confirm the enhancement brought about by the presence of quantum wells