Raman and Infrared Spectra Study of GaN1-xPx Ternary Alloys Grown by MOCVD
用MOCVD方法制备的GaN_(1-x)P_x三元合金的喇曼与红外光谱

Both Raman and infrared reflection spectra for a series of high P compositional GaN 1-xP x alloys grown by means of light-radiation heating,low-pressure metal-organic chemical vapor deposition are investigated.The Raman spectra of GaN 1-x-P x alloys,recorded in backscattering geometry,exhibit four new vibrational modes at 256,314,377,and 428cm -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.The frequency of the A 1(LO) mode is found to redshift,which is attributed to the effects of alloying and strain.The infrared reflectance spectra show another new mode near 630cm -1,which is associated with the E 2(TO) phonon mode that results from a random distribution of the P atoms in GaN 1-xP x alloys and elimination of lattice translational symmetry.