采用微波等离子体化学气相沉积法通过控制痕量杂质制备了高质量单晶金刚石材料,并对其结构与光学性能进行综合评价。通过紫外可见吸收光谱和光致发光谱分析了晶体的杂质及含量;采用拉曼光谱、摇摆曲线及X射线白光形貌束分析了不同质量单晶体的晶体结构及结晶质量;通过偏光显微镜综合评价了不同质量单晶金刚石的晶体结构和缺陷。结果证明:获得的高纯单晶金刚石含有少量的缺陷、杂质,其位错应力场以聚集状均匀分布,高纯单晶金刚石与微掺氮单晶金刚石在紫外可见近红外波段的透过率最高可分别达到71.58%和71.27%,接近单晶金刚石的理论透过率(71.6%),且在本征红外吸收波段,高纯金刚石晶体相对微掺氮单晶金刚石,对称性较好,样品吸光度较小。控制痕量杂质制备的高质量单晶金刚石膜有望应用于光探测器探头和光学窗口。

In this study, microwave plasma chemical vapor deposition was used to control the trace impurities for preparing high-quality single-crystal diamond materials, the structural and optical properties of which were comprehensively evaluated. Further, the impurity contents of the crystals were analyzed using ultraviolet (UV)-visible absorption spectroscopy and photoluminescence spectra. The crystal structures and quality of the single crystals exhibiting different qualities were analyzed based on the Raman spectrum, X-ray rocking curve, and X-ray white-light morphology beam. Subsequently, the crystal structures and defects of a single-crystal diamond exhibiting different qualities were evaluated under a polarizing microscope. The obtained high-purity single-crystal diamond contains a few defects and impurities, and its dislocation stress field is uniformly distributed in the aggregate state. The maximum transmittances of single-crystal diamonds with high purity and low-doped nitrogen in the UV visible near-infrared (UV-visible-NIR) band are 71.58% and 71.27%, respectively, which are approximately similar to the theoretical value of transmittance (71.6%) for diamond. In the intrinsic infrared absorption band, the lattice symmetry of high-purity diamond crystals is better, whereas the absorbance is smaller than that of low-concentration nitrogen-doped single-crystal diamonds. The high-quality single-crystal diamond film prepared by controlling the trace impurities is expected to be used as an optical detector probe and an optical window.