ISOELECTRONIC IN-DOPING EFFECT IN GAN FILMS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

The isoelectronic In-doping effect in GaN films grown by metalorganic chemical vapor deposition was investigated by using Raman scattering, scanning electron microscopy (SEM), and x-ray and photoluminescence (P L) measurements. In our study, the phonon spectra of films remain shar p without alloy formation after incorporation of small amounts of In a toms. The SEM pictures of the sample surface reveal greatly reduced na nopits indicating better surface flatness that is also supported by th e multiple interference effect in the PL signals. More importantly, is oelectronic doping has caused the linewidth at 15 K of the near-band-e dge emission of GaN to decrease sharply to 10 meV or less, reflecting improved optical property. (C) 1998 American Institute of Physics.