采用电子辅助-热丝化学气相沉积法(EA-HFCVD)在硅片上沉积出晶粒尺寸为30 nm的均匀金刚石膜.生长过程中,预先加6 A偏流生长1 h,然后在0.8 kPa条件下,无偏流生长3 h.光致发光谱中存在4个发光中心分别位于1.682 eV, 1,564 eV, 1,518 eV和1.512 eV的发光峰.1.682 eV处发光峰源于衬底硅原子掺杂于膜中引起的缺陷;其他发光峰源于金刚石晶格振动声子.光致发光强度越大对应的缺陷密度越大,从而降低了场发射域值电场强度,其关键可能源于金刚石膜电导型晶界.%Nano-crystalline diamond films with a grain size of 30 nm were deposited on pretreated Si wafer surface via electron assisted-hot filament chemical vapor deposition method with a bias current of 6 A applied for 1 h, followed with no bias current for 3 h at 0.8 kPa gas pressure. A photoluminescence (PL) study was carried out by Raman spectrometer in the wavelength range of 700～900 nm. Four emission bands centered at 1.682 eV, 1.564 eV, 1.518 eV and 1.512 eV were observed. The 1.682 eV feature was attributed to the silicon impurity from the substrate, the 1.564 eV feature to the local vibration mode of the defect, and the others bands to diamond lattice phonons. The higher the PL intensity is, the more the defects have and the lower the threshold field is. The key of the mechanism for this result may be due to conducting grain boundaries, which allows the field emission to be much easier.
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