Effect of composition on the band gap of strained InxGa1-xN alloys

The band gap of pseudomorphically strained InxGa1-xN alloys has been measured using optical absorption spectroscopy. X-ray diffraction measurements indicated that the in-plane lattice parameter of the InxGa1-xN film equaled that of the underlying GaN layer. For strained InxGa1-xN, it was determined that the band gap shift versus composition is given by dE(g)/dx=-4.1 eV for x<0.12. Our results contradict some recent reports that InxGa1-xN has a relatively small bowing parameter. Possible reasons for the discrepancies are discussed. (C) 2003 American Institute of Physics.