Vertical-Tunnel-Junction (VTJ) Solar Cell for Ultra-High Light Concentrations (>2000 Suns)

A novel architecture of cell structure tailored to ultra-high( >2000 suns) concentrationratios is proposed. The basic solar cell consists of two p-n junctions connected in series by a highly doped tunnel diode with the metallic contacts located laterally. The tunneling connection allows using direct band-gap semiconductor compounds aiming to optimize the absorption of the spectrum. The performance of the novel architecture is investigated up to ultra-high concentration using TCAD software. Simulations show its viability for developing a new generation of solar cells to increase the potential in terms of efficiency and cost reduction of ultra-high concentrator systems. The solar cell does not show any degradation with concentration and efficiency as high as 28.4% at 15000 suns has been obtained for a preliminary design.

keywords: Vertical solar cells, concentrator photovoltaics, gallium arsenide (GaAs), tunnel diode, series resistance.