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With the advancement of technology, the development of the semiconductor material has experienced first-generation element semiconductor germanium, silicon, the second generation of compound semiconductor GaAs, InP, now people are increasingly concerned about the third-generation semiconductors. The third-generation semiconductor materials, the wide band gap semiconductor material, has the potential can not be compared to the previous two generations of semiconductors in the high-temperature, high-frequency, high-power devices and short wavelength optoelectronic devices, is the hot spot in the world semiconductor materials and device research areas. Of SiC and GaN in electronic devices, more mature, and more in the light emitting device, the III-nitride and ZnO based compound. Now, SnO 2 by more and more attention. SnO 2 is a direct band gap wide bandgap semiconductor materials, compared with the other materials of SnO 2 significant advantages. First, the large band gap, the exciton binding energy, 3.6eV at room temperature, and 130meV; the preparation temperature low, good chemical stability. Therefore, SnO 2 is a short wavelength light emitting material a good candidate. As an excellent functional material, SnO 2 film on the transparent conductive oxide (TCO) film, and the chemical gas sensors and other fields to obtain a wide range of applications and have not been reported, but the light emitting device. One reason is that by an ordinary method (e.g., magnetron sputtering, CVD, spraying, etc.) prepared SnO 2 the quality of the thin film transistor is not high, contain more defects, the light-emitting characteristics, are not suitable for fabricating a semiconductor light emitting device . Another reason is that the difficulties encountered SnO 2 p-type, although there are p-type SnO 2 reported, but the film quality is not high, the electrical properties are not ideal, still not suitable for production of light-emitting devices. Happily nearly two years in the high quality SnO 2 preparation has made certain achievements, has prepared a single crystal SnO 2 2 , to the electrons by guide to the valence band caused by the UV emission peak was observed at room temperature, but the authors did not reported doping substance SnO 2 thin film electrical properties impact. In this context, the paper studies the MOCVD prepared doped SnO 2 thin films and its characteristics. The paper work and the results are as follows: 1. Using MOCVD method, high-purity (C 2 H 5 ) 4 Sn as a tin source , the high purity the (C 2 H 5 ) 2 Zn as zinc source, high purity O 2 as an oxidant. the purity N 2 as the carrier gas, respectively, in the sapphire (0001), a silicon (111) and on a quartz substrate was prepared 1% (atomic ratio) Zn-doped SnO 2 film (SnO 2 : Zn film). The XRD pattern shows that on a silicon (111) and a quartz substrate prepared SnO 2 : Zn film, appeared (110), (211), (220) and (321) a plurality of diffraction peaks , SnO 2 polycrystalline thin film of rutile structure; appears only a thin film on the sapphire (0001) substrate was prepared (200) of a diffraction peak, with a preferred orientation along the a-axis. The test results show that a thin film on the sapphire (0001) substrate was prepared having a good film quality. 2 using the MOCVD method, on the sapphire (0001) substrate was prepared 1-10% doping of SnO 2 : Zn film. Prepared films are of SnO 2 rutile structure along the a-axis preferential growth orientation. The optical transmission spectra of the samples showed that the transmittance of the film in the visible range of greater than 80%. Calculated according to the curve of the absorption coefficient - a photon energy range of the optical band gap to obtain a film is 3.54eV-3.56eV. Calculated based on the interference fringes of the film transmittance spectrum, a film thickness of 1-1.4μm, and to calculate the relationship between the refractive index of the thin film of different doping concentration and wavelength. Tested by X-ray photoelectron spectroscopy (XPS) analysis of the composition of the film. Tested using the four-probe method, and the Van der Pauw method, the electrical properties of the film, and analyzed. Air annealing of the film structure and optical properties. MOCVD method undoped of SnO 2 film and 1-12% doped SnO 2 : In thin films prepared on sapphire (0001) substrate. The XRD tests show all film SnO 2 rutile structure and preferential growth along the a-axis orientation. The scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) diagram shows the prepared thin film is a single crystal thin film. XPS showed that 3% doping of SnO 2 : In the film surface there are non-ideal stoichiometric oxide, the surface of the film In, Sn atomic ratio of 3.16:97. Transmittance of the film in the visible region is greater than 88%, optical band gap decreases as the dopant concentration increases. Tested using the four-probe method, and the Van der Pauw method, the electrical properties of the film, and analyzed.
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