Preparation Technology And Physical Property Of AlN Nanowires

One-dimensional(1D) AlN nanostructure is an important ceramic semiconductor with wide band-gap,it has many outstanding physical properties because of size effect and dimensionality effect.However,there are still several problems about preparation at present,and investigations of physical properties are rarely reported.This paper recites the whole process about preparation of AlN nanowires by template method.Firstly,template with monodisperse metal nano-particles is made by vapour phase deposition,and then AlN nanowires are synthesized by chemical vapour phase deposition.Scanning electron microscope(SEM) is used to observe the appearance of template. The result is that with the enhance of experimental temperature,time of constant temperature and gas velocity,diameter of nano-particles increases.In special experimental conditions monodisperse Cu or Al nano-particles templates with fine monodisperse, symmetrical diameter,great dispersion density and high percentage of coverage have been made.So the effective method to make monodisperse metal nano-particles template has been summarized.In the conditions that N₂(600torr),maintaining 240min at 1200℃,AlN nanowires with smooth face,ordered tropism and symmetrical diameter have been synthesized by using monodisperse Al nano-particles template and chemical vapour phase deposition. Besides the influence of size of nano-particles on the template,the diameter of AlN nanowires increase with enhance of experimental temperature and time of constant temperature according to the results of SEM.The crystal structure of AlN nanowires is hexagonal wurtzite according to the result of high resolution electron microscope(HRTEM) and selected area electron diffraction(SAED),their growth are along[001]direction of hexagonal AlN and growth mechanism is vapor-liquid-solid(VLS).The results of X-ray diffraction(XRD),Ultraviolet-visible light spectrua(U-V),Raman spectrua(Raman) show that component of nanowires is hexagonal AlN with a small quantity of Al₂O₃.U-V spectra shows that 651nm absorbing band of AlN nanowires is wider than AlN bulk materials' because of small size effect and quanta effect;Raman spectra of AlN nanowires has no different with Raman spectra of AlN nano-particles,and do not display special optical property of AlN nanowires;In photoluminescence spectra,there is an oxygen-related violet-blue PL band,that is a different optical property of AlN nanowires compared with AlN bulk materials.