Light-Harvesting and Photon Management in GaAs Solar Cells for Photovoltaic-Thermoelectric Hybrid Systems

The utilization of solar energy in photovoltaics is limited due to the band gap of the materials. Hence, photovoltaic–thermoelectric hybrid system was proposed to utilize solar energy in the full spectrum of AM1.5G. On this basis, a novel design of GaAs solar cell is proposed in this paper for the full spectrum absorption in the cell structure, which consists of an ultra-thin GaAs layer with nanocones on the surface and a nanogrid–AZO–Ag back contact. The Finite Difference Time Domain method is used to analyze the full spectrum absorption features for TE and TM polarizations over the incident angles varying from 0° to 60°. The designed structure shows high absorption in the full spectrum. For GaAs layer, it is shown that the solar usable energy for GaAs solar cells in 300–900nm is absorbed by GaAs almost perfectly due to the anti–reflection property of the nanocone array. The absorbed energy in the back contact in the longer wavelengths over 900nm is due to the Fabry-Perot and the localized plasmonic resonances. The structure can collect full-spectrum incident photons efficiently in GaAs solar cells for the application of photovoltaic–thermoelectric hybrid system.