The Preparation For ZnO Nanomaterials By CBD At Low Temperature

As a kind of II-VI direct band gap semiconductor material, Zinc oxide (ZnO) has a largeexciton binding energy which is60meV. And at room temperature condition, the forbiddenband width of ZnO is3.37eV. Possessing of many unique properties, including the thermalstability and light penetration, ZnO material has a large range of conductivity and biologicalcompatibility. ZnO material, recently, has been widely used in the preparation for many kindsof nano devices, ZnO nano field effect transistor (FET), ZnO nano light-emitting diodes(LEDs), ZnO nano generator, ZnO photodiode and ZnO chemical sensors, for instance. Thestructure of the material has a vital effect on the performance of this material based device. Asa reason of that, the controllable growth of ZnO nano material plays an important role in thepreparation of ZnO based nano devices. In this paper, ZnO nano structure is separately grownon Si and GaAs substrates by chemical bath deposition (CBD) at low temperature. Theexperiments with different growth parameters which can affect the structure of ZnO materialare conducted. A growth method which can control the structure of ZnO material is figuredout. Specific content is as follows:On the one hand, ZnO material is prepared on both Si and GaAs substrates by CBDtechnique. Through controlling the concentration of reaction solution and growth time,different morphologies of ZnO nanostructures are prepared. After a series of tests, includingSEM, TEM and XRD, the results about the morphology and crystallization properties of ZnOnanostructure are concluded. The results show that the formation of ZnO arrays on Sisubstrate is regularly arranged, and a nanowall structure is grown on GaAs substrate. Theanalysis is conducted about the ZnO structure of different growth time on Si and GaAssubstrates, and a conclusion about growth mechanism of ZnO structure on different substratesis made.On the other hand, one-dimensional ZnO nanowires with different growth orientationand side are prepared by CBD at low temperature. The influence of ZnO seed layer thicknesson growth orientation and size is studied. SEM results show that with the increase of seedlayer thickness, the density of nanowires is increasing and the growth orientation is graduallyswitched from horizontal direction to vertical direction. The diameter of nanowires, however,decreases and the length goes down. The diameter and length of ZnO nanowires can bechanged an order of magnitude by adjusting the thickness of ZnO seed layer. The result ofAFM reveals the physical mechanism about growing one-dimensional ZnO nanowires withdifferent growth orientation and size by changing the thickness of ZnO seed layer.