Study On The Preparation,Cu Doping And Properties Of High Quality In₂O₃ Nanowires

Indium oxide（In₂O₃）is a common n-type semiconductor material with wide band gap.Itsnanostructure has attracted much attention in recent years.Because of its many advantages such as high chemical stability,it is also considered as a very suitable host for doped dilute magnetic semiconductor materials in many studies.At the same time,electrons have the properties of charge and spin.Diluted magnetic semiconductor（DMS）materials are widely used in many fields,such as semiconductor integrated circuits and computer software,because they have the ability to control these two properties at the same time and have good electrical and optical properties.In this paper,pure In₂O₃ nanowires were prepared by chemical vapor deposition and their morphologies were controlled.On the basis of pure In₂O₃nanowires,they were doped with Cu and Cu-N.The morphology,composition,structure and magnetic properties of pure In₂O₃ and Cu、Cu-N doped In₂O₃ nanowires were studied by means of characterization and performance test methods such as SEM,XRD,EDS,XPS,TEM,XAFS,SQUID and first-principles calculation.Systematic analysis and research have been carried out,and the following conclusions have been drawn:1.Pure In₂O₃ nanowires were grown on substrates by chemical vapor deposition（CVD）in a solid-liquid-gas mechanism.Firstly,the morphology of In₂O₃ nanowires was controlled by four factors in control variate method,including reaction temperature,gas flow rate,substrate position and reaction time.The optimum growth conditions of In₂O₃ nanowires were obtained:heating temperature of 1050℃,argon flow rate of 40sccm,substrate growth distance of 3cm and reaction time of 2 hours.Then the samples prepared under the optimum growth conditions were characterized and tested:XRD test showed that the structure of the product was In₂O₃ cubic bixbyite structure;EDS and XPS measurements showed that the samples contained In and O elements,oxygen vacancies,and the valence state of In was In³⁺.TEM measurements showed that In₂O₃ nanowires were uniform in thickness and smooth in surface,no impurities were attached,and the product was single crystal In₂O₃ with excellent crystallinity.2.In₂O₃ nanowires doped with Cu and Cu-N were prepared by chemical vapor deposition,the two doped samples were characterized from composition,morphology,structure,magnetism and theory,and we obtained the following conclusions:EDS,XRD and XPS measurements showed that the products contained Cu and N elements and distributed evenly,and the doped Cu and N displaced In³⁺and O^2-,respectively;TEM measurements showed that no impurities were attached to the doped In₂O₃ nanowires and the products were single crystals;SEM images showed that the morphologies of the two doped samples were good,with a diameter of 200-300 nm,a uniform density distribution and a length of more than 10μm;XAFS spectra showed that the Cu element in the two doped samples exist in the form of+1 valence;M-H curves showed that both doped samples have room temperature ferromagnetism,and the contribution of N element is greater;Finally,two models of InCuO and InCuNO were established in theoretical analysis.It’s found that the system of Cu-doped In₂O₃ is antiferromagnetic ground state,the system of Cu-N co-doped In₂O₃ is stable ferromagnetic ground state,and the system of Cu-doped In₂O₃ can be obviously transformed to ferromagnetic by N co-doping.