| Gallium nitride (GaN) is an excellent chemical semiconductor material and also is one of the most advanced semiconductors in the world. In fact, GaN has been regarded as one of the most promising materials for the fabrication of opto-electronic devices operating in the blue and near-ultraviolet (UV) regions, for instance light-emitting diodes (LEDs) and laser diodes (LDs), because it has large direct energy band gap of 3.4eV at room temperature. These light sources have promising applications and potential market demands for the high-density storage of opto-information, high-speed laser print, high-brightness and dynamic display in all colors, solid light sources, signal detectors and communication. In addition, GaN has been attracted much attention as a candidate for fabrication of high temperature, high frequency and high power devices. After 1990, the realization of some pivotally technical methods and the development of materials growth and devices technics made GaN to be the research focus of the world. MOCVD, MBE and HVPE have become dominating techniques to grow GaN materials. Among these methods, MOCVD is the most important and widely used by researchers. But now large-scale application of GaN devices is confined for the reason of costly equipments and complicated technics. Many research institutes and universities in the world are trying to grow GaN materials with simple and low cost methods.Nanometer-sized materials such as nanowires and nanotubes have gained considerable attention because of their potential applications in both mesoscopic research and the development of nanodevices. GaN at nano-dimensions, in particularly, as nanowires, is a good candidate for fabrication of nanometer sized opto-electronic devices. Since 1999, the synthesis of GaN structures has become one of the research focuses.In this paper, we have successfully synthesized high purity one-dimensionalGaN nano structures and high quality GaN crystal films with novel and simple two steps growth pattern. The composition, the structure and the photoluminescence properties of the fabricated products were analyzed in detail. The growth mechanism of two steps growth pattern were primarily discussed. We also summarized the rules and the effects to the growth of GaN nano structures and GaN films.1. One-dimensional GaN nano structures were synthesized on different substrates through nitriding 03263 films grown by radio frequency (r.f.) magnetron sputtering or electrophoresis. The synthesized GaN nano structures by the two steps growth pattern are hexagonal single crystal GaN. The photoluminescence (PL) properties of the formed one-dimensional GaN nano structures gained at room temperature revealed nicer results. The high resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray (EDX) suggested that the two steps growth pattern overcame the shortcomings of templet-confined reaction mechanism, catalytic reaction growth based on vapor-liquid-solid (VLS) mechanism and oxide-assisted growth mechanism, which would introduce contaminates unintentionally.2. The morphologies of one-dimensional GaN nano structures were affected greatly by substrates. We can get different one-dimensional GaN nano structures by choosing different substrates. Among the products, smooth and straight GaN nanowires on quartz substrates, long and transparent GaN nanobelts on sapphire substrates, short GaN nanorods on Si substrates and GaN nanopoles on GaAs substrates were found, respectively.3. The nitridation programs also affect the surface morphology of GaN nanowires. Different nitridation programs have produced straight and smooth GaN nanowires and herringbone GaN nanowires on quartz substrates, respectively.4. Choosing suitable nitridation temperature can get ideal one-dimensional GaN nano structures. Ga2O3 attached on the surface of one-dimensional GaN nano structures would be found if the nitridation temperature is low (<90...
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