Structure properties of GaN/sub 1-x/P/sub x/ ternary alloys grown by metal-organic chemical vapor deposition

Abstract

GaN-rich side of GaN/sub 1-x/P/sub x/ ternary alloys have been successfully synthesized by light-radiation heating and low-pressure metal-organic chemical vapor deposition. The Ga 3d and P 2p core level peaks of the GaN/sub 1-x/P/sub x/ films show that P atoms in GaN/sub 1-x/P/sub x/ do partly occupy the N site but also is incorporated as interstitials of GaN/sub 1-x/P/sub x/ by means of X-ray photoelectron spectroscopy. X-ray diffraction spectra show that the (0002) peak of GaN/sub 1-x/P/sub x/ shifts to smaller angle with increasing P composition and the GaN/sub 1-x/P/sub x/ films are still of a typical hexagonal structure. The Raman spectra of GaN/sub 1-x/P/sub x/ films, recorded in backscattering geometry, exhibit four new vibrational modes at 256, 314, 377 and 428 cm/sup -1/ compared with an undoped GaN sample. Those modes are assigned to the so called quasi-local mode induced by P in GaN, disorder-activated scattering and gap modes related to the Ga-P bond vibrations, respectively.