Isoelectronic In-doping effect in GaN films grown by metalorganic chemicalvapor deposition

The isoelectronic In-doping effect in GaN films grown by metalorganic chemi cal vapor deposition was investigated by using Raman scattering, scanning e lectron microscopy (SEM), and x-ray and photoluminescence (PL) measurements . In our study, the phonon spectra of films remain sharp without alloy form ation after incorporation of small amounts of In atoms. The SEM pictures of the sample surface reveal greatly reduced nanopits indicating better surfa ce flatness that is also supported by the multiple interference effect in t he PL signals. More importantly, isoelectronic doping has caused the linewi dth at 15 K of the near-band-edge emission of GaN to decrease sharply to 10 meV or less, reflecting improved optical property. (C) 1998 American Insti tute of Physics. [S0003-6951(98)01331-X].