The Investigation Of The Synthesis Of ZnO Films And The Fabrication Of One Dimension GaN Nano Structure Through Ammoniatng Ga₂O₃/ZnO Films

Zinc oxide (ZnO) and gallium nitride (GaN) are two excellent compoundsemiconductor materials.Both of them are the most advanced semiconductors in theworld.ZnO and GaN crystal have similar lattice character of wurtzite structure for thelattice mismatches of orientation a and c are only 1.9% and 0.4% respectively.GaNhas a direct energy band gap of 3.4 eV at room temperature,so it is a perfect materialfor the fabrication of optoelectronic devices,especially for blue/green light emittingdiodes (LEDs) and laser diodes (LDs).GaN material can also be fabricated for whiteilluminating devices which can replace the illuminating system used all through.GaNmaterial can realize light emitting from infrared to ultraviolet that consist the wholevisible light range,then the solid display possessing tricolor which consist red,yellowand blue can be produced.At present,GaN is mainly used to fabricate high speed andmicrowave devices,electric charge coupling devices,dynamic memorizers,highbrightness blue and green light emiting diodes,ultraviolet detectors.GaN material alsobring the revolution for the memory technology in IT industry.The width of theforbidden band of ZnO is about 3.37eV at room temperature and the exciton bindingenergy of ZnO is 60meV,which improve the mechanism of exciting and emiting ofZnO material greatly.The obtain of the optical pumping ultraviolet laser make itbecome the popular photoelectricity material.ZnO material is widely used for surfaceacoustics devices,solar battery,piezoelectricity devices and buffer layer.One dimension nano materials obtain widely attention recently for the uniquephysical property and potentially application in nano electronics and opticalelectronics.One dimension nano materials have important application value for basicstudy and fabricating new generation nano devices.At present,GaN nano material iswidely studied.GaN nano material has widely application prospect in high electronmobility nano devices and full color flat display. For the absence of the optimum substrates used for the growth of GaN films,weused ZnO as buffer layers and Si as substrates replacing expensive sapphire tofabricate GaN films.Unfortunately when NH3 is used as reaction preceding of thegrowth of GaN films,ZnO will volatilize in ammonia ambience at hightemperature.While ZnO films are fabricated in different ambience especially inammonia ambience,the mechanism of the volatilization processing and the effect toGaN films haven't been reported.We studied the structure,morphology,compositionand stability of ZnO films.We also studied the effect mechanism of ZnO buffer layersto search for a new method to fabricate GaN films on Si substrates.GaN nanomaterials were synthesized through ammoniating Ga2O3 films with the assistance ofthe volatilization of ZnO layers to explore new approach to fabricate GaN nanomaterials. ZnO films and Ga2O3/ZnO films were sputtered on Si(111) substrates using radiofrequency (rf) magnetron sputtering system at first.Then ZnO films were annealed inair and ammonia ambience respectively in tube quartz furnace.It was found that ZnOfilms annealed in air ambience have good quality. When annealed in ammoniaambience at 700℃,ZnO films have good value.While ZnO volatilized gradually alongwith the increase of the temperature.And when the temperature is high above700℃,ZnO volatilized completely.When Ga2O3/ZnO films were ammoniated inammonia ambience,ZnO layers volatilized completely at high temperature and Ga2O3reactived with NH3 to fabricate GaN one dimension nano structure.This articlediscusses the condition of the volatilization of ZnO films in ammonia ambience andput forward the reactive mechanism of the volatilization.The primary rule and factorsof the synthesization of GaN nano materials were summarized and the mechanism ofthe synthesization of GaN nano materials with the assistance of the volatilization ofZnO layers were put forward. In chapter one,the fundamental properties,the fabrication technics and the mainapplication of GaN and ZnO are presented.The application of ZnO used as the bufferlayers for GaN films is discussed.The concept of nano structure,the technics andmechnism of the synthesization of nano materials,and the application of nanomaterials are also presented.The cause of the choose of the research subject is given inchapter one. In chapter two,the experiment instruments,raw materials and reagents,and themeans to characterize the samples are presented.The principle and formation ofsputtering system and ammoniating system.The structure properties of the sampleswere examined by a RIGAKU D/max-γA X-ray diffraction(XRD) meter with Cu Kαradiation (λ=1.54178?);The composition of the samples was examined by PV-9900X-ray energy dispersive spectroscopy(EDS) meter, TENSOR27 fourier transforminfrared spectrophotometer(FTIR),and VG ESCALAB MKII X-ray photoelectronspectroscopy(XPS) meter;The morphology of the samples was studied by HITACHIH-8010 scanning electron microscopy(SEM) and HITACHI H-800 transmissionelectron microscope(TEM);The structure property of the crystal lattice was studied byPhilipTecnai 20U-TWIN high resolution transmission electron microscope(HRTEM)and the selected area electron diffraction(SAED).LS50 spectrophotometer was appliedto study the optical property of the samples. In chapter three,ZnO films were sputtered using radio frequency magnetronsputtering system,then ZnO films were annealed in air and ammonia ambiencerespectively.The properties and morphology of the ZnO films fabricated in the twoambience were studied.The volatilization of ZnO in ammonia ambience was studiedand the reaction mechanism was put forward.The effect of the volatilization to theZnO buffer layers for GaN films was discussed. In chapter four,ZnO films and Ga2O3 films were sputtered in turn on Sisubstrates,then Ga2O3/ZnO films were ammoniated in tube quartz furnace.ZnO layersvolatilized and in the process of the volatilization Ga2O3 reactived with NH3 tosynthesize GaN one dimension nano structure.The ammoniating temperature,theammoniating time,the width of ZnO layers were studied to find the effect to theproperty and morphology of GaN nano structure.Transmission electron...