吸收辐射复合金刚石膜的制备及光学研究

Study on the compound film of diamond for absorbing radiation

采用微波等离子体化学气相沉积(MW-PCVD)和直流热阴极辉光放电等离子体化学气相沉积(DC-PCVD)两种方法相结合,制备出一种吸收辐射的复合金刚石膜,它对宽光谱范围的光辐射具有99%—99.2%的吸收率,同时具有较低的反射率和透过率.随着黑色吸收辐射金刚石层厚度的增加,复合金刚石膜的热导率将小幅度降低,但黑色金刚石膜层厚度小于15μm时,复合金刚石膜的热导率都在16W.cm-1.K-1以上,这满足吸收辐射复合金刚石膜的高导热需求.用热阴极DC-PCVD方法制备的黑色吸收辐射金刚石膜层在1500—1600cm-1范围和1350cm-1处出现了对应于非金刚石碳相的宽带拉曼峰.随着甲烷浓度的增加,金刚石膜中会出现更多的非金刚石碳相成分,即石墨等非金刚石碳相在金刚石膜中富集,复合金刚石膜的透光性也越来越差.黑色吸收辐射金刚石层直接沉积在高纯金刚石片上,具有较高热导率和吸收率,并且该复合膜背面具有绝缘性.

The solar radiation has significant impact on the earth climate and environment, so it’s important to detect it. High thermal conductivity and high absorptivity material for absorbing radiation is highly needed to improve the performance of the radiation detector. The compound diamond films were deposited using microwave plasma chemical vapor deposition （MW-PCVD） and hot cathode direct current plasma chemical vapor deposition （DC-PCVD） methods. The absorptivity of the compound diamond film is 99%—99.2%. With the increase of the thickness of black diamond layer, the thermal conductivity of the compound diamond film decreases a little, but the thermal conductivity is always larger than 16 W/K·cm when the thickness of black diamond layer is less than 15 μm and so it is still a high thermal conductivity material. The black diamond layer deposited on high purity diamond film by hot cathode DC-PCVD method has apparent wide Raman peaks at 1500—1600 cm-1 and 1350 cm-1 which correspond to non-diamond carbon phase. With the increase of methane, this non-diamond carbon phase also increases. As the non-diamond carbon phase, like graphite, increases, the transmissivity of the compound diamond films decreases. The black diamond layer deposited on the high purity diamond acts as the heat sink and has high surface adhesion property, and high thermal conductivity.