Investigation of effects of source flux on the properties of p-GaN flim grown by MOCVD

GaN:Mg films have been grown on sapphire at low temperature by metal-organic chemical vapor deposition(MOCVD),and the properties of p-GaN:Mg films with different CP2Mg source fluxes and mol ratios of Ⅴ and Ⅲ(Ⅴ/Ⅲ) are studied.The results show that the screw dislocation density is decreased under increasing Ⅴ/Ⅲ ratio,and the quality of p-GaN crystal is improved.And when the Ⅴ/Ⅲ ratio is 3 800,the CP2Mg flux is up to 170 sccm,and the p-GaN film,whose narrower full width at half maximum(FWHM) of(002) plane is 232,is obtained.It also shows that the effects on decreasing edge dislocation only by increasing Ⅴ/Ⅲ ratio are not obvious.