Preparation And Characterization Of Gallium Nitride And Gallium Oxide Based Low-Dimensional Nanostructures

The development of semiconductor materials has mainly gone through three stages.compared with the first two generation of semiconductor materials,the third generation of semiconductor materials with wide band gap width,high breakdown electric field,the high thermal conductivity,high electron saturation rate and higher ability to resist radiation,also known as the high temperature the semiconductor material and wide bandgap semiconductor material,as a representative of the third generation of semiconductor materials,gallium nitride(GaN) and gallium oxide(GaO) nano structure materials are widely used in blue leds,UV LED,photoelectric detector,and HEMT devices,etc.Due to its excellent properties and wide applications,the preparation and characterization of GaN two-dimensional thin film materials and GaO based gallium and gallium indium alloy nanoparticles or nanodroplets have become a hot topic of current research.Because of GaN single crystal material is expensive and difficult to obtain,so the way to get the gallium nitride thin film is mainly made use of sapphire substrate under hydrogen atmosphere heterostructure epitaxial growth,thin film defect density is big,the quality is low,and use of hydrogen as the reaction atmosphere while it is possible to improve the reaction chamber temperature,accelerating the rate at which reactants migrate on the substrate surface,optimize the quality of the GaN epitaxial layer,but also brought the poor safety and disadvantages such as expensive.Therefore,how to grow gallium nitride thin films with high quality under safer and cheaper nitrogen atmosphere becomes the focus of people's attention.While replacing nitrogen atmosphere brings a series of technical difficulties,The biggest difficulty lies in how to epitaxial grow high-quality GaN nucleating layer under the atmosphere of nitrogen,this needs us from growth time,reaction temperature,?/? aspects and so on than to find a set of matching the best growth parameters.In this paper,first of all,under the atmosphere of nitrogen,we epitaxial grown the gallium nitride films on(0001) sapphire substrate by MOCVD method,and by changing the reaction cavity pressure,reaction temperature,reaction time and ?/?parameters studied the influence of different conditions on the nucleation layer surface morphology,and looking for the best parameters.Then we studied the re-annealing of gallium nitride epitaxial grown in MOCVD system,by changing the annealing temperature,time and atmosphere,study the changes of the surface morphology of the annealed under different parameter condition,optimum annealing conditions are obtained by AFM scanning image analysis,as well as the regularity of annealed under different conditions.Finally,GaO-based eutectic gallium indium alloy nanodroplets were prepared by van der Waals(vdW) stripping method.The size and morphology of the droplet were characterized by AFM,and the mechanism of droplets formation was explained.