Al-doped ZnO Powders And Films Prepared By Reverse Micelle Microemulsion Method

ZnO is a kind of II-VI semiconductor material with a direct and wide bandgap, which has hexagonal wurtzite cystal structure. Up to date, ZnO has attracted a lot of concern among the researchers due to its excellent properties on piezoelectric, photoelectric, gas-sensing and pressure-sensitive and so on. Al-doped ZnO thin film is considered as a promising 3G semiconductors owing to its low resistivity, superior optical, electrical and stability properties. Especially, as transparent conductive film (TCO), ZnO thin film is comparable to the Sn-doped In2O3 (ITO) with a high quality. However, the preparation of Al-doped ZnO thin film via physical method is hindered in the industrial production owing to its difficult processes and high cost. Therefore, new preparation process with low cost, simple process and precise ratio is in great need.In this paper, the Al-doped ZnO nano powders were prepared via the reverse micelle microemulsion method, and the-Al-doped ZnO nanocystalline thin films with different doping component were synthesized on glass substrates through the dip-coating and spin-coating methods, and the preferred c-axis orientation can also be obtained.The dried sample derived from the precursor solution was analyzed by DTA-TG method, and according to the samples treated at different temperatures, the improved process of heat treatment was proposed. Furthermore, the influence of addition amount of precursor solution on the crystal structure, orientation and average grain size of Al-doped ZnO powders and films were investigated by XRD, UV-VIS spectra. The results show that with the increasing of Al doping into ZnO film, the diffraction peaks of ZnO shift to lower degree, and the interplanar crystal spacing is increased. Furthermore, a blue shift can be seen at the UV absorbing edge, and the minimum in UV absorbing edge to the short wave direction is obtained when the doping component is 3%(Al3+/Zn2+mol). According to the Burstein-Moss effect, the carries concentration of ZnO dependence of Al doping component is investigated theoretically.