CVD金刚石膜的场发射机制

利用热灯丝化学气相沉积方法在光滑的钼上沉积了金刚石膜，用扫描电子显微镜和Raman谱对金刚石膜进行了分析。结果表明金刚石膜是由许多金刚石晶粒组成，晶粒间界主要是石墨相，并且在膜内有许多缺陷。金刚石膜的场发射结果表明高浓度CH4形成的金刚石膜场发射阈位电场较低浓度CH4形成的金刚石为低。这意味着杂质（如石墨）和缺陷（悬挂键）极大地影响了膜的场发射性能。根据以上结果，提出了一种CVD金刚石膜的场发射机制即膜内的缺陷增强膜内的电场，石墨增大电子的隧穿系数以增强CVD金刚石膜的场发射。

Field emission mechanism of CVD diamond films

The diamond films deposited on polished molybdenum by hot filament chemical vapor deposi－ tion (HFCVD) were investigated by scanning electron microscopy (SEM) and Raman spectroscopy. The results show that the films are composed of diamond crystallites, the crystal boundaries are mainly graphite and there are a number of defects in the films. The characteristic measurements of field emis－ sion indicate that the diamond film formed by high density of CH4 exhibits lower threshold electric field required for emission than the diamond film deposited by low density of CH4. It means that the impurity (such as graphite) and defects (dangling bonds) in the films greatly affect their field emission. Based on the results, a field emission mechanism of CVD diamond films is put forward, i.e. the dangling bonds in the films which enhance the electrical field in the films and the graphite in the films which increase tunneling coefficient of electrons can improve the field emission of CVD diamond films.