InxGa1-xN/GaN band offsets as inferred from the deep, yellow-red emission band in InxGa1-xN

The deep, yellow photoluminescence band well known in GaN has been studied in InxGa1-xN (x less than or equal to 0.14) grown pseudomorphically on GaN. The peak energy E-p of the band is found to shift gradually to the red with increasing x according to E-p = 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 Delta E-c(x)approximate to 2.02x (eV) and Delta E-v(x)approximate to 1.26x (eV) for x less than or equal to 0.14. (C) 1999 American Institute of Physics. [S0003-6951(99)02826-0].