碳酸钙掺杂对Ⅰb型金刚石沿不同晶面生长行为的影响

Effect of CaCO_(3) Doping on Growth Behavior of TypeⅠb Diamond along Different Crystal Faces

作为天然金刚石生长环境的碳酸盐,研究其掺杂对人造金刚石晶体生长行为的影响具有重要的学术价值。本文运用高温高压下的温度梯度法,将碳酸钙(CaCO_(3))按照不同比例掺杂到金刚石合成腔体内的碳源中,用以研究其掺杂对金刚石分别沿(100)或(111)晶面生长行为的影响。利用光学显微成像对掺杂合成金刚石晶体形貌的表征表明:随着碳酸钙掺量的增加,沿(100)面生长的金刚石晶形由塔状变为板状且出现了裂晶、连晶现象,晶体颜色先变浅再变黑,内部出现了包裹体;同样,沿(111)面生长的金刚石晶形由板状逐渐变为塔状且出现了裂晶、孪晶现象,晶体颜色逐渐变黑,内部包裹体增多。用激光拉曼光谱对掺杂金刚石晶体质量的表征表明:随着碳酸钙掺量的增加,沿(100)或(111)面生长的掺杂金刚石的拉曼峰位偏移量均增大,半峰全宽均变大。这说明碳酸钙掺杂使得金刚石晶格畸变增加、内应力变大。本文对碳酸钙掺杂影响沿两不同面生长金刚石的晶形、颜色、内部质量等行为的成因进行了分析,为本课题后续研究奠定了基础。

It is of great academic value to study the influence of carbonate doping on the growth behavior of synthetic diamond crystals.In this paper,CaCO_(3) was doped into the carbon source in the diamond synthesis cavity at different ratios using the temperature gradient method at high pressure and high temperature(HPHT).The purpose of the study is to investigate the effect of CaCO_(3) doping on the growth behavior of diamond along the(100)or(111)crystal plane,respectively.The crystal morphology of doped synthetic diamonds was studied by optical microscopy.The results show that with the increase of the CaCO_(3) content,the crystal shape of diamond growing along the(100)plane change from tower to plate accompanied by crack crystal or crystals stock.The color of the crystal becomes lighter and then darker,and the inclusions appear in diamond.Besides,the crystal shape of diamond growing along(111)surface gradually changes from plate to tower accompanied by crack and twin crystals phenomena.With the increase of the CaCO_(3) content,the color of diamond crystals gradually becomes darker,and more inclusions appear in diamond.The Raman spectroscopy results show that with the increase of CaCO_(3) content,the Raman peak position shifts of doped diamond growing along(100)or(111)plane increase,and the full width at half maximum(FWHM)becomes larger.This indicates that the doping of CaCO_(3) increases crystal lattice distortion and internal stress of diamond.In this paper,the causes for the effect of CaCO_(3) doping on the crystal shape,color,internal quality and other behaviors of the diamond growing along the two different faces were analyzed,which lays the foundation for the subsequent study of this topic.