BAND-GAP SEPARATION IN INGAN EPILAYERS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

Two energetically-separated resonance structures were found in photore flectance (PR) spectra of three-dimensional InxGa1-xN epilayers (0.05 less than or equal to x less than or equal to-0.2) grown by metalorgan ic chemical vapor deposition. Energy difference between the two struct ures was nearly constant about 50 meV for all x examined. The broadeni ng parameter of each structure was nearly independent of x (similar to 50 meV), indicating that each separated region has rather homogeneous net potential fluctuation. The photoluminescence (PL) peak energy agr eed with the resonance energy of the lower-energy PR structure? showin g nearly zero Stokes-Like shift at room temperature. Observation of a single PL peak indicated that photoexcited carriers were effectively c orrected into the separated regions having lower PR resonance energy. (C) 1998 American Institute of Physics.