以磷化铁为添加剂沿(111)面生长磷掺杂金刚石大单晶

掺杂是调控金刚石性能的一种重要手段。本文采用温度梯度法,在5.6 GPa、1 312 ℃的条件下,选用Fe₃P作为磷源进行磷掺杂金刚石大单晶的合成。金刚石样品的显微光学照片表明,随着Fe₃P添加比例的增加,金刚石晶体的颜色逐渐变深,包裹体数量逐渐增加,晶形由板状转变为塔状直至骸晶。金刚石晶形的变化表明Fe₃P的添加使生长金刚石的V形区向右偏移,这是Fe₃P改变触媒特性的缘故。红外光谱分析表明,Fe₃P的添加使金刚石晶体中氮含量上升,这说明磷的进入诱使氮原子更容易进入金刚石晶格中。激光拉曼光谱测试表明,随着Fe₃P添加比例的增加,所合成的掺磷金刚石的拉曼峰位变化不大,其半峰全宽(FWHM)值变大,这说明磷的进入使得金刚石晶格畸变增加。XPS测试结果显示,随着Fe₃P添加比例的增加,金刚石晶体中磷相对碳的原子百分含量也会增加,这意味着添加Fe₃P所合成的金刚石晶体中有磷存在。

Growth of P-Doped Diamond Large Single Crystals Along (111) Surface with Fe3P as Additive

Doping is an important means to control the properties of diamond. In this paper, the P-doped diamond large single crystals were synthesized by temperature gradient method at 5.6 GPa and 1 312 ℃ using Fe₃P as the phosphorus source. The results of the optical micrographs of diamond samples show that as the amount of Fe₃P additve increases, the color of diamond crystals becomes darker, the number of inclusions increases in the crystals, and the crystal shape transforms from plate to tower, even to skeletal. It indicates that the V-shaped growth region shifts to the right when Fe₃P is added. This is due to Fe₃P has effect on the properties of the catalyst. IR spectra of P-doped diamond reveal that the concentrations of nitrogen impurity in the diamond crystals increases with the increase of the Fe₃P content. It indicates that the entry of phosphorus induces nitrogen atoms to enter the diamond lattice more easily. Raman spectra results show that with the increase of Fe₃P content, the Raman peak positions of the synthesized diamond change little, but the FWHM becomes larger. This suggests that the entry of phosphorus increases the crystal lattice distortion of diamond. XPS test results show that with the increase of Fe₃P, the content of P relative to C in diamond crystal also increases. It means that phosphorus are present in the diamond crystals synthesized by Fe₃P addition.