| Zinc oxide (ZnO) is a novelⅡ～Ⅵsemiconductor with a direct wide band gap of～3.3eV. Al-doped ZnO (ZAO) and ZnO/Zn2SiO4 nanocomposites based on a SiO2 matrix, which have excellent photoelectronic properties and extensive application, have greatly attracted many researchers attentions. The preparations and photoelectronic properties of Al-doped zinc oxide and ZnO nanocomposites are investigated, and their luminescence mechanism and the relations of synthesis, structure and property are discussed, too.The main contents were summarized as follows:1. Photoelectronic properties, structure and applications, Al-doped zinc oxide, ZAO, are reviewed briefly.2. ZAO powders, with different Al-doped content, are prepared with chemical reagents of Zn(C2H3O2)2·2H2O, AlCl3 and (COOH)2·2H2O by the sol-gel method; ZnO nanocomposites are prepared using Zn(C2H3O2)2·2H2O, APS(NH3CH2CH2 CH2Si(C2H5O)3) by the sol-gel technique and calcining at different temperature, time;3. Thermal decomposition processes of samples are analyzed by TG; Structure, composition and morphology of samples are investigated by FTIR,XRD and TEM; Optical properties are investigated by UV-Vis and PL. Luminescence mechanism of samples is discussed, too.4. Studied on structural and optical properties of Al-doped zinc oxide, it is found that the mean diameter of nanocrystalline ZAO powders is the biggest at calcined temperature of 850℃, calcined time 1 hour and Alwt％=2. Ultraviolate absorption edge of the sample is located at 367 nm (3.36eV), which is much more "blue shift" as compared with bluk materials. The average optical trasmittance of the sample is above 80％in the range of 385nm to 800nm. The strong blue-light emssion emerge in 468nm. 5. Studied on structural and optical properties of ZnO/Zn2SiO4/SiO2 composites, it is found that the optimum structure combination of ZnO nanocomposites is determined at calcined temperature of 850℃, calcined time 2 hours and ZnO wt％=20. Ultraviolate absorption edge of the nanocomposites will increase and energy gap will decrease with ZnO content increasing; Ultraviolet-light and blue light emission intensities of the nanocomposites are greatly enhanced, too; A green-light emssion is appearing while ZnO content above 20％.
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