The Study Of Preparation And Structure Of GaN Materials By Sol-gel Method

Gallium Nitride(GaN)is aⅢ-Ⅴcompound semiconductor with a direct and wide bandgap,and can be extensively used for optoelectronic and microelectronic devices.At present,the research of GaN has become the hotspot and in the forward position of global semiconductor field.In this dissertation,GaN nanoparticles and films were prepared in Sol-Gel method rather than with CVD,MOCVD,MBE,or other methods,which is very simply and low-cost with innovation.The sol precursor was synthesized by Ga₂O₃ taken as Gallium source and crtric acid as comlexing agent,and GaN materials were prepared through the process of aminating treatment in high temperature.The results measured in XRD and TEM showed that the GaN nanoparticles with the optimal properities were sythesized while the precursor with a neutral PH value was has been aminated at 950℃for 90min.The structure of as-prepared undoped GaN materials belongs to Wurtzite,and the grains in the films orientated preferentially along to(002)plane.With the increase of the anealing temperature,the crystal state of GaN grains measured in SEM and AFM become better and surface roughness is smaller.The results of PL spectra show that the band-edged emitting peak of GaN is at 350nm.Moreover,there are two phonon styles of A₁(TO)and E₁(TO)in Raman spectra,and there are Ga-N bonds on the surface of the powder in XPS spectra.Further,there is blue emitting band of 450-490nm in the PL spectra of Mg:GaN films,which has a red shift towards a low energy with the increase of impurity concentration.Structures and stability of Ga_nN₃(n=1-6)and Ga_nN₂(n=2-7)clusters have been studied using the density functional theory(DFT).The most stable structures of all ground states of Ga_nN₃(n=1-6)clusters show that N-N bonds play a crucial role in the stability,n=3 is the magic number of Ga_nN₃(n=1-6)and n=6 is the magic number of Ga_nN₂(n=2-7).The most of strongest frequency of all clusters are approach with wurtzite GaN's phonon module,which can explanation the formation of nano-materials.