An InGaAs graded buffer layer in solar cells

Abstract

This paper uses an InGaAs graded buffer layer to solve the problem of lattice mismatch and device performance degradation. In the graded buffer layer, we choose the “transition layer" and the “cover layer" to accommodate the 3.9% mismatch. No threading dislocations were observed in the uppermost part of the epitaxial layer stack when using a transmission electron microscope (TEM). We analyze the factors which influence the saturation current. Simulation data shows that the cells grown by metal organic vapor phase epitaxy (MOVPE) have considerable open circuit voltage, short circuit current, and photoelectric conversion efficiency. Finally we propose that InP may have great development potential as a substrate material.