Band-gap separation in InGaN epilayers grown by metalorganic chemical vapor deposition

Two energetically-separated resonance structures were found in photoreflectance (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 metalorganic chemical vapor deposition. Energy difference between the two structures was nearly constant about 50 meV for all x examined. The broadening 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 agreed with the resonance energy of the lower-energy PR structure? showing nearly zero Stokes-Like shift at room temperature. Observation of a single PL peak indicated that photoexcited carriers were effectively corrected into the separated regions having lower PR resonance energy. (C) 1998 American Institute of Physics.