Low‐Temperature Photoluminescence Investigation of Carbon‐Doped AlGaAs Grown by MOVPE on Vicinal Substrates

Abstract

AlGaAs is promising absorber material for multi‐junction solar cells (MJSC) for its tunable bandgap to match various bandgap combination designs. However, the path to achieving high‐quality AlGaAs for solar cell application remains to be determined. In this study, we grow and characterize carbon‐doped p‐Al0.375Ga0.625As on exact and vicinal GaAs(0 0 1) substrates, using metal‐organic vapor phase epitaxy (MOVPE). Low‐temperature photoluminescence (PL) measurement is performed in the range from 6 K to 300 K. The Arrhenius plot of PL intensities reveals an increasing trend for non‐radiative recombination in conjunction with increasing miscut angle. The presence of atomic ordering that inversely correlates to the miscut angle is proposed to explain the PL linewidth and peak energy dependency on substrate orientation. The conflicting tendency of non‐radiative recombination and ordering with miscut angle are further validated using solar cell devices. A slightly vicinal substrate is recommended for AlGaAs solar cells according to our observation.