Low-temperature Growth Of AlN Nanocones And Synthesis And Composition Regulation Of Ternary AlInN Nanostructures

As an important member of the third-generation semiconductors, AIN is well known for its wide bandgap, small electron affinity, high stability, superior thermal conductivity and so on. One-dimensional (ID) AIN nonomaterials have promising applications in field emission (FE)、optoelectronic devices. To date, various 1D AIN nanostructures including nanotubes, nanowires, nanobelts and nanocones have been synthesize by different methods, such as chloride-assisted chemical vapor deposition, carbon nanotube-confined reaction, arc-discharge, direct nitridation of Al powers, etc. Among these 1D nanostructures, AIN nanocone arrays exhibit good FE properties because of their sharp apexes and large aspect ratio, which have potential applications in the areas of vacuum micro-electronic devices and field emission flat panel displays. Nowadays, the research of AIN-based cold cathodes is still on the experimental stage, and AIN nanoscale field emitters are difficult to be used in practical application due to the two following factors:(1) The high growth temperature disabled the direct deposition of AIN nanostructures on ITO-coated glass plates; (2) AIN has high resistance due to its superwide bandgap, which is unfavorable for the electron transport in the AIN nanostructures and emission from the surface. In this thesis, we studied the low-temperature growth of AIN nanocones, and investigate preliminarily the synthesis and composition regulation of ternary AlInN nanostructures. The results are briefly summarized as follows:1. We developed a convenient route to the preparation of AIN nanocone arrays at atmospheric pressure and temperature lower than 600℃ by optimizing experimental conditions. By this route AlN nanocones can be synthesized at 500℃, which is the lowest temperature up to date. The nanocones grown at low temperature have diameters of ～10 nm in tips and length of ～200 nm, which exhibit good FE properties. The result provides a low-temperature growth technology to deposit AlN-based cold cathode on the ITO-coated glass plates.2. Ternary AlInN 1D nanostructures were synthesized at first time through the chemical reaction among AICl3、InCl3 and NH3, and their composition could be regulated in the range of 0.88<x< 1. With the deposition temperature of 600～700℃, the In content of the products increases and then decreases as elevating the vaporization temperature of InCl3. The composition of the AlxIn1-xN alloy nanostructures could be regulated in the range of 0.95< x< 1,0.93< x< 1, and 0.88 < x< 1 at the deposition temperature of 700,650 and 600℃ respectively. Phase separation occurs if the Al/In ratio in the AlxIn1-xN products exceeds the preceding range.