| III nitride semiconductors are currently experiencing the most exciting photoelectric characteristics development. As an important photoelectric exposure, field emission properties of III nitride semiconductors have attracted widely interestingness of researchers. In this thesis, considering the present embarrassment of field emission development, it analyze by the numbers the status, history and prospect of field emission from semiconductors. Then, the physical substance of excellent field emission performances of III nitride semiconductors were investigated both theoretically and experimentally, to more improve the field emission capability of semiconductors, it is also supplied some possible techniques and thoughts in this thesis. Finally, based on authors' analysis and apperception, it shows the prospective research orientation of field emission from semiconductors. The main research work of this thesis as follow:1. A theoretical model based on the band bending theory was developed for explaining the field emission mechanism of wide-bandgap semiconductors (WBGSs). As an example of field emission from III nitride semiconductors, it analyzes the excellent field emission performance of cubic boron nitride (c-BN). The results draw a new thinking to explain the field emission mechanism, in which it is considered that the band bending, as well as the negative electron affinity (NEA), is of equal importance to the excellent field emission performances of WBGSs. In other words, the band bending contributes to supply enough quantities of effective electrons, and the NEA characteristic helps to free electrons from the surface potential. The calculated results are in agreement with the experiment data.2. An electron-emission theoretical model integrating the change in the grain size of nanocrystalline based on quantum theory was established. The nanocrystalline c-BN films field enhancement effect and nanocrystalline AlxGa1-xN composite films are researched theoretically. The results show that the emission current from nanocrystalline grain films is far larger than that from regular grain films or bulk. The field emission enhancement may originate from the NEA strengthen and the band bending increased because of the widen bandgap in nanocrystalline films. The nanocrystalline field emission enhancement is also close related with the composite index and emission temperature for AlxGa1-xN films. 3. The important effects of deposited parameters to high quality BN film preparation are investigated. It shows that, the substrate temperature and the negative bias are two key factors, to improve the films performance, it is necessary to select suited other parameters, such as, deposition time, work pressure, nitrogen Concentration, buffer layers. The high quality BN with 90% cubic phase content, good adhesive and 1μm thickness is successfully deposited and the phase content of BN films can be controlled by changing the disposition parameter.4. Field emission properties from different cubic phase content BN films are studied, the results show there are better field emission performance from high cubic phase BN films than from low cubic phase BN films. Expect the geometry field enhancement, the enhancement effect of field emission from BN films with cubic phase content increasing is mainly rooted in the accumulated electron enhancing and the surface potential barrier lowing. Generally, there is bigger field emission current from sp3 bonding than sp2 bonding. 5. The high oriented gain silkworm-like AlN films are prepared by reactive magnetron sputtering It is found that nucleation energy and nucleation density caused by sputtering pressure is a key factor of high orientation films preparing. Furthermore, other sputtering parameters to the effect of AlN orientation growth are investigated, the results show that, power density, and wafer temperature and substrate are also the important parameters for the preferential orientation of AlN.6. Tropism mechanisms for field emission from semiconductor films a...
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