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本文在5.6 GPa,1250—1340?C的条件下,利用温度梯度法,以FeNiMnCo合金为触媒,沿籽晶的(100)晶面成功合成了不同晶形的优质Ⅰb型和Ⅱa型金刚石大单晶.利用激光拉曼附件显微镜,分别对上述不同温度下合成的两类金刚石样品上表面(100)面的中心区域及棱角区域进行观察分析.研究发现,Ⅰb型和Ⅱa型金刚石大单晶(100)晶面上从中心到棱角处黑色纹路的分布逐渐变黑变密集;另外,随着金刚石合成温度的升高,Ⅰb型金刚石大单晶(100)面上黑色纹路由稀疏逐渐变稠密,而Ⅱa型金刚石大单晶的黑色纹路较为稀疏;Ⅰb型金刚石大单晶的形貌特征表现为从低温晶体的不规则分布过渡到中温、高温晶体的典型树枝状分布.Ⅱa型金刚石大单晶(100)面特征随温度变化规律与Ⅰb型的类似.这两类金刚石大单晶表面特征的差异可能是由于Ⅱa型金刚石具有比Ⅰb型更小的生长速度和更少的氮含量.最后,对两类塔状金刚石大单晶进行拉曼光谱测试分析,结果表明Ⅱa型金刚石大单晶的品质较Ⅰb型金刚石大单晶好.
Under the conditions of 5.6 GPa and 1250-1340? C, the temperature-gradient method and the FeNiMnCo alloy were used to synthesize large-sized single-type and single-type diamond single crystal of type Ib and IIa along the (100) The laser Raman attachment microscope was used to observe and analyze the central and angular regions of the upper surface (100) of the two types of diamond samples synthesized at different temperatures respectively. It was found that the type Ⅰb and type IIa diamond single crystal (100 ) Black crystal distribution becomes darker and denser at the center from the center to the corner. In addition, with the increase of the diamond synthesis temperature, the black lines on the (100) Ⅱ a type diamond single crystal is more sparse black lines; Ⅰ b diamond single crystal morphology from the irregular distribution of low-temperature crystal transition to the middle temperature, high temperature crystal typical dendritic distribution. Ⅱ a-type diamond single crystal ( 100) surface features are similar to that of type Ib.The variation of the surface characteristics of the two types of diamond single crystal may be due to the smaller growth rate and less nitrogen content of Type IIa diamond than Type Ib Finally, the Raman spectra of two types of tower diamond single crystal were measured and the results showed that the quality of Ⅱ a diamond single crystal was better than that of Ⅰb type diamond single crystal.