In x Ga 1−x N/GaN band offsets as inferred from the deep, yellow-red emission band in InxGa1−xN

Abstract

The deep, yellow photoluminescence band well known in GaN has been studied in InxGa1−xN (x⩽0.14) grown pseudomorphically on GaN. The peak energy Ep of the band is found to shift gradually to the red with increasing x according to Ep=2.20−2.02x (eV). As in the case of GaN, the deep band in InxGa1−xN is assigned to shallow donor-deep acceptor pair recombination. The data show that the deep acceptor level does not follow the valence band edge. It is therefore assumed to be pinned to a reference level common to GaN and InxGa1−xN. The band offsets between GaN and strained InxGa1−xN evaluated under this assumption, are found to be given by ΔEc(x)≈2.02x (eV) and ΔEv(x)≈1.26x (eV) for x⩽0.14.