| Popis: |
ZnO is one of the most studied materials of the II-VI oxide materials that derive continuous attention of the researchers worldwide since forties (Bunn 1935). Because of its current and possible applications in several novel devices, renewed interest has emerged and several reviews (Liu et al, 2005; Tsukazaki et al, 2005), and conference proceedings are published exclusively for ZnO nano crystallites similar systems at Singapore (2005), (2009) and Changchan, China (2006) to explore the feasibility of commercial application for future devices. Yet the ream of novel devices from this wonderful material is yet to be accomplished in full (Wellings, et al, 2008). With a wide band gap of 3.2 eV and a large exciton binding energy of 60 meV at room temperature, ZnO, line GaN, will be important for blue and ultraviolent optical devices. ZnO has several advantages over GaN in this applications range however, the most important being its longer exciton binding energy and the ability to grow single crystal substrates. Other favourable aspects of ZnO include its broad chemistry leading to many opportunities for wet chemical etching, low power threshold for optical pumping, radiation hardness and biocompatibility. Together, these properties of ZnO make it an ideal candidate for a variety of devices ranging from sensors through to ultra-violet laser devices and nanotechnology based devices such as displays. As fervent research into ZnO continues, difficulties such as the fabrication of p-type ZnO that have so far stated that the development of devices had over come (Yang etal, 2008). To give a quantitative report on the state of art of ZnO nanocrystals is quite difficult and an attempt has been made to survey the chemical growth of this system in this study. The chemical solution growth of ZnO nano thin films composed of nano crystallites using a two step double dip chemical deposition method has been discussed In detail in this chapter. The growth and characterization of nano structures of ZnO has been reported by Wang (Wang, 2004). Mitra et al (1998) has prepared Zinc Oxide thin films using chemical deposition technique. The structural, morphological properties of the prepared films are characterized using X-ray diffraction and scanning electron microscope. They have used Zn salts as precursor and successfully synthesized ZnO films. The growth of highly textured Zinc oxide (ZnO) thin films with a preferred (101) orientation has been prepared by employing chemical bath 2 |
