SPATIALLY-RESOLVED PHOTOLUMINESCENCE AND RAMAN-SCATTERING EXPERIMENTSON THE GAN SUBSTRATE INTERFACE

We present results from spatially resolved photoluminescence and Raman experiments on the substrate interface region of wurtzite GaN layers. We show that the broad photoluminescence band with an intensity maxim um at 2.4 eV is not an intrinsic property of GaN. We found that this p hotoluminescence band is strong only near the interface. Our investiga tions reveal that both the substrate interface and a region of structu ral reorientation of the layer near the interface act as a source of t he photoluminescence. (C) 1996 American Institute of Physics.