大尺寸掺硼宝石级金刚石单晶的高温高压合成及电学性质研究

在5.4GPa、1200～1400℃条件下,进行掺硼金刚石单晶的合成研究。成功合成出了重0.2g,径向尺寸达6.0mm的优质掺硼金刚石单晶。考察了合成体系中硼添加量对晶体透光度的影响。利用伏安特性和霍尔测试,得到了掺硼金刚石单晶常温电阻率、霍尔系数及霍尔迁移率和合成体系中硼添加量的关系。研究发现,随着合成体系中硼添加量的增加,晶体的电阻率和霍尔迁移率都呈下降趋势;霍尔系数随硼添加量的增加先下降后上升。随着硼添加量的增加:晶体常温电阻率下降,表明硼杂质已进入到金刚石晶体中。霍尔迁移率的下降,可能是晶体缺陷增多对载流子散射所致。霍尔系数先减小后增大,这可能与进入金刚石的硼元素量增大及晶体缺陷增多有关。

Studies on synthesis and electrical properties of large boron-doped gem diamond crystals under HPHT

In the paper,the synthesis of boron-doped diamond single crystals was studied under 5.4GPa and 1200-1400℃.The boron-doped diamond crystal,with 0.2g in weight and 6.0mm in size,was synthesized successfully.The effect of the content of boron added in synthesis system on the light transmittance of diamond crystals was studied.By current-voltage characteristics and hall measurements,the relationships of room temperature resistivity,hall coefficient,hall mobility and the content of boron added in synthesis system,were obtained.We found that the room temperature resistivity and the hall mobility were all decrease by the content of boron additive increasing.While the content of boron additive increases,the hall coefficient decreases firstly,and increases afterwards.By the content of boron additive increasing,the decrease of room temperature resistivity of the boron-doped diamond crystal indicates that boron has entered into diamond crystal.The reason,why hall mobility decreases by the increase of boron additive,may be that the carrier is scattered by increasing crystal defects.The change of hall coefficient is due to the increase of the boron entering into diamond crystals and crystal defects.