| Considerable efforts have been focused on the study of multiple compound semiconductor materials such as indium gallium nitride (InrGa1-xN), aluminum indium nitride (Al-In1-xN), aluminum gallium nitride (Alx-Ga1-xN), indium gallium phosphorus (InGaP) and magnesium zinc oxide (MgrZn1-xO) for the reason that the band gap of these materials can be modulated by varying the relative components. They have been used to manufactur semiconductor optoelectronic devices and photoelectronic devices, and have very broad application prospects in light emitting diodes (LED), laser (LD), UV detector, thin-film transistors, and memorizer etc.In recent years, much attention has been focused on the preparation and luminescence properties of nano, thin film and doped aluminum oxide material due to its advantages such as wide band gap (8.7eV), high breakdown voltage (6～8mv/cm), high dielectric constant (～9), chemical and thermal stability. Indium oxide is an important optoelectronic information materials with a direct band gap of3.7eV Aluminum and indium are both III elements, and Al2(1-x)In2xO3can be considered as an alloy of aluminum oxide and Indium oxide. Aluminium-Indium oxide has a band gap that can be modulated by changing the constituent elements ratio. And that it has wide band gap, large modulation range, nontoxic and pollution-free characteristics. Therefore, Al2(1-x)In2xO3should be a very promising material in the field of UV transparent semiconductor, short-wavelength light-emitting and superlattice quantum wells. In this paper, Al2(1-x)In2xO3films with different x(0.1-0.9) were prepared and analyzed, and its structure, optical and electronic properties are investigated in detail.In this paper, the main research work and results are shown as follows:1. The In2O3epitaxial films were prepared on different substrates at600℃by metal-organic chemical vapor deposition. High purity In(CH3)3, O2and ultra-high purity N2were used as the organometallic source, oxidant and carrier gas, respectively. The multi-functional X-ray diffractometer results indicated that the sample deposited on Y-stabilized ZrO2(YSZ)(111) substrate had a single alignment structure and the best crystal quality. Therefore, the InO3films were deposited on YSZ(111) substrates at different temperatures from500℃to700℃by MOCVD. The structural, optical and electrical properties of the samples dependent on substrate temperature were investigated. XRD and Ψ scan results showed that the thin film grown at600℃had the best crystalline quality. HRTEM and ω rocking curve were carried out on the sample to obtain the epitaxial relationship diagram. The epitaxial relationship between the film and the substrate was In2O3(222) YSZ (111), with In2O3[011] YSZ [011]. The average transmittance of the samples in the visible wavelength range was over77%and the band gap was about3.62-3.65eV. The film prepared at600℃had the minimum value of3.62eV. The highest Hall mobility of the samples was27.7cm2v-s-1at600℃, meanwhile, the carrier concentration and the resistivity were5.13×1018cm-3and4.4×10-2Ωcm, respectively.2. Based on the above experimental condition, the Al2(1-x)In2zO3films with different indium content (0.1<x<0.9) were deposited on YSZ(100) at the substrate temperature of600℃by MOCVD to investigated the effect of different components on the film properties. High purity In(CH3)3, O2and ultra-high purity N2were used as the organometallic sources, oxidant and carrier gas, respectively. XRD showed that, as the In content decreased, the structure of the films changed from better crystal quality of cubic structure In2O3to worse gradually, and the diffraction peak was not observed when the Al content was high. The average transmission of the obtained films in the visible range was over73%, and the optical band gap could be modulated from3.68eV to4.68eV by changing the composition content. Due to the higher growth temperature of aluminum oxide, the Al2(1-x)In2xO3films were deposited on YSZ(100) and YSZ(111) at the substrate temperature of700℃in the same experimental conditions. XRD results indicated that, as the In content decreased, the crystal quality of films deteriorated gradually and the structure changed from cubic structure In2O2to amorphous or microcrystalline structure. The diffraction peak was not observed when the Al content was high. HRTEM carried out on the film of Al0.4In1.6O3showed that the crystal quality was better, but there existed composition of polycrystalline. The epitaxial relationship between the film and the substrates were In2O3(100) YSZ(100) and In2O3(222) YSZ(111), respectively. The compositions of Al2(1-x)In2xO3films were consist with the experiment enactment values. The average transmission of the obtained films in the visible range exceeded74%, and the optical band gap could be modulated from3.63eV to4.63eV by changing the composition content. The carrier mobility of the samples reduced continuously with the increase of the Al content, the resistivity had a minimum value when the Al content was20%, then increased monotonically. |
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