| Zinc oxide is a II-VI wide band-gap (3.3eV) compound semiconductor with wurtzite crystal structure. Due to the large exciton binding energy of 60meV, which ensures the high efficient excitonic emission at room temperature, it is regarded as one of the most promising materials for fabricating efficient ultraviolet (UV) and blue light emitting devices. Since the first observation of the stimulated ultraviolet emission at room temperature, ZnO has become another hotspot in the region of UV light emitting researching. Al-doped ZnO(ZAO) thin films are emerging as an alternative potential candidate for ITO (Sn-doped In2O3) films recently not only because of their comparable optical and electrical properties (high optical transparency in visible range,infrared reflectance and low d.c. resistivity) to ITO films,but also because of their higher thermal and chemical and chemical stability under the exposure to hydrogen plasma than ITO.In this dissertation, Al-doped ZnO thin films on Si (100) and quartz substrates were prepared by using electron beam evaporation technique. X-ray diffraction (XRD), photoluminescence spectra, transmittance spectra, Van der Pauw experiment were employed to study the optical and electrical properties of ZnO:Al thin films,The experimental results show that the ZnO:Al films prepared by electron beam evaporation can be greatly improved by annealing of in oxygen ambient, The XRD patterns indicated that they possess a polycrystalline hexagonal wurtzite structure with a preferred (002) orientation. The electrical properties, including conductivity, Hall mobility and carry concentration were changed with the annealing temperature. The conductivity had the maximum value of 1165Scm-1 for the film annealed at 500 oC. The temperature-dependent photoluminescence were measured in the temperature range of 80-300K. The free exciton emission, the neutral-donor bound exciton emission and the ioned-donor bound exciton emission were observed in low-temperature PL spectra. |
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