Emitter-less, back-surface alternating-contact solar cell

Abstract

The disclosure provides an emitter-less solar cell design featuring p-or-n type GaAs with alternating p-n junction regions on the back-surface of the cell, opposite incident solar irradiance. Various layers of p-or-n type GaAs are interfaced together to collect charge carriers, and a thin layer of AlGaAs is applied to the front and back surfaces to prevent recombination of charge carriers. In some embodiments, the layered and doped structure generally provides an AlGaAs window layer of about 20 nm doped to about 3x(l0¹⁸) cm⁻³, a GaAs absorption layer of about 1200 nm doped to about 2x(l0¹⁷) cm⁻³, an AlGaAs heterojunction layer of about 20 nm doped to about 3x(l0¹⁸) cm⁻³, and a GaAs contact layer of about 20 nm doped to about 1x(l0¹⁹) cm⁻³. Additionally, AlGaAs BSF-heterojunction layer and GaAs BSF-contact layers each have a depth of about 20 nm and are doped to about 3x(l0¹⁸) cm⁻³ and lx(10¹⁹) cm⁻³ respectively. The heterojunction layer, and contact layer are doped to a conductivity type opposite the absorption layer.