Molecular Beam Epitaxy of Wide-Bandgap InAlAsSb on InP Substrates for an All Lattice-Matched Triple-Junction Solar Cell

We present molecular beam epitaxy growth of novel InAlAsSb lattice-matched to InP for use in an all lattice-matched triple-junction design. Given the unexplored nature of this material, we studied the effect of substrate temperature (T
_sub
) and group-V to group-III flux ratio (V/III) on surface morphology, Sb-incorporation, and peak photoluminescence (PL) energy. Decreased T
_sub
and increased V/III ratio, i.e. reduced adatom mobility at the growth front, increased the peak PL energy, likely due to a reduction in phase separation.