Hybrid III-V/SiGe solar cells on Si substrates and porous Si substrates

TL;DR

This paper presents a novel hybrid GaAsP/SiGe solar cell architecture on silicon substrates with a porous silicon layer that reduces cracks and improves performance, advancing tandem solar cell technology.

Contribution

Introduction of a porous silicon layer in a GaAsP/SiGe tandem solar cell to suppress cracks and enhance efficiency on silicon substrates.

Findings

Reduced crack propagation due to porous silicon layer

Improved solar cell performance with new architecture

Lower shunt resistance issues addressed

Abstract

A tandem GaAsP/SiGe solar cell has been developed employing group-IV reverse buffer layers grown on silicon substrates with a subsurface porous layer. Reverse buffer layers facilitate a reduction in the threading dislocation density with limited thicknesses, but ease the appearance of cracks, as observed in previous designs grown on regular Si substrates. In this new design, a porous silicon layer has been incorporated close to the substrate surface. The ductility of this layer helps repress the propagation of cracks, diminishing the problems of low shunt resistance and thus improving solar cell performance. The first results of this new architecture are presented here.