Study On Gallium Oxide And InGaO Nanomaterials Grown By CVD

Gallium oxide（Ga₂O₃）belongs to the fourth generation of semiconductor materials.Its band gap is 4.4 to 5.3e V.It can absorb photons with a wavelength of less than 250nm.It has high physical stability at room temperature and certain corrosion resistance.It can be applied in solar blind detectors,oxygen/carbon dioxide gas sensors and light-emitting diodes,and other fields.Gallium oxide has been confirmed to contain six isomeric structures.Among them,monoclinic gallium oxide（β-Ga₂O₃）has the most stable chemical and physical properties,is suitable for high temperature,high pressure,and corrosive environments,and is currently the most widely studied and used structure.Chemical vapor deposition（CVD）is a relatively simple and cheap preparation method.At present,metal oxide nanomaterials such as Zn O and Mg O have been successfully prepared by chemical vapor deposition.In this paper,gallium oxide and indium gallium oxide nanomaterials were grown by chemical vapor deposition.The main research contents are as follows:1.The electrical properties of intrinsic gallium oxide were calculated using theβ-Ga₂O₃unit cell using first-principles calculations based on density functional theory（DFT）.Calculation results show that monoclinic gallium oxide is an indirect bandgap semiconductor material.Gallium atoms in gallium oxide have two non-equivalent positions.In theβ-(In_xGa_1-x)₂O₃ simulation,it is necessary to determine the appropriate replacement position.The simulation found that the gallium ion binding energy substituting the octahedral site is smaller,which is the preferred site for doping.After adding In element,the band gap ofβ-(In_xGa_1-x)₂O₃ system decreases with the increase of In content,and the n-type conductivity of the system increases.The simulation calculation provides a theoretical basis for the experiment of preparing gallium oxide-based semiconductor materials.2.Gallium oxide nanomaterials were prepared by chemical vapor deposition,and the surface morphology and physical properties of the samples were controlled by changing the growth temperature,growth time,growth substrate,oxygen content,and catalyst.The characterization results show that the test sample is a nanowire of monoclinic gallium oxide.The test results show that gallium oxide nanowire materials with a clear structure and high crystal quality can be obtained when the reaction temperature is 1000°C and the reaction time is 80 minutes.In the absence of catalysts,sapphire substrates are easier to generate gallium oxide nanomaterials than silicon substrates.In a high-concentration oxygen environment,the surface of the nanowire will be covered with more small grains,and the surface will become rougher.When using Au as a catalyst,more nanomaterials can be obtained,but the nanowires tend to grow with more crystal faces.Usingβ-Ga₂O₃ and(In_xGa_1-x)₂O₃ nanomaterials,a solar-blind ultraviolet detector was fabricated.The ultraviolet photodetector prepared byβ-Ga₂O₃ has a photo-dark current ratio of 103 orders of magnitude under 254nm illumination,has a stable photoresponse under different bias voltages,and has certain self-power supply characteristics when the bias voltage is 0V.3.In GaO nanomaterials were prepared by chemical vapor deposition.The suitable reaction temperature is 900°C,and under this condition,nanowire samples with complete structure and uniform size can be obtained.When the reaction time is 80min,(In_xGa_1-x)₂O₃nanowires with high crystal quality can be obtained.Under high oxygen concentrations,the surface of(In_xGa_1-x)₂O₃ nanowires is rougher and covered with small grains.When the argon-oxygen ratio is 3,the XRD test shows that the crystal quality of the sample is the best.The photoluminescence spectrum test shows that(In_xGa_1-x)₂O₃ nanowires have emission peaks of blue light,purple light,and yellow light under the excitation light of 254nm.In GaO nanomaterials have better conductivity,resulting in a lower photo-dark current ratio for UV photodetectors based on them.