硫氢协同掺杂金刚石大单晶的高温高压合成及性能研究

The synthesis and performance research of n-type semiconductor diamond single crystal has been the key scientific issue in the field of diamond synthesis. Both theoretical and experimental researches show that the doping with single element is extremely difficult to obtain the n-type semiconductor diamond single crystal, exhibiting excellent electrical performance. In this study, the synthesis of n-type semiconductor diamond single crystal (≥5 mm) with excellent performance will be investigated under high pressure and high temperature conditions by selecting catalyst solvent and additives, adjusting the proportion of additives and optimizing the synthesis process. Furthermore, the concentration, existing forms and interaction mechanism of S and H in diamond structures will be further understood by means of synchrotron radiation X-ray scanning technology, atomic tunnel scanning, microscopic Raman, infrared spectrum, etc. Especially, the effects of the co-doping H element on the electrical transport property of n-type semiconductor diamond doping with S element will be studied emphatically. The in-depth study of this project benefits not only to the successful preparation of n-type semiconductor diamond, but also to reveal the formation mechanism of natural diamond and the further understanding of the mantle and the core questions.

n型半导体金刚石单晶的合成与性能研究一直是国际金刚石合成领域的科学热点问题，理论和实践均表明：单一元素掺杂难以制备出电学性能优异的n型半导体金刚石单晶。本项目将借助高温高压极端合成条件，通过优选适合硫氢协同掺杂的触媒溶剂和添加剂、调节添加剂的比例、优化合成工艺来研制具有优异n型半导体功能特性的金刚石大单晶(≥ 5mm)。借助同步辐射X射线、离子束分析、原子隧道扫描技术、显微拉曼和红外光谱等先进测试手段，深入研究氢与硫在金刚石中的浓度、存在形式、与缺陷间的相互作用机制，重点研究氢协同掺杂对硫掺杂n型半导体金刚石的电输运调制机制与规律。该项目的研究不但有望制备出具有优异性能的n型半导体金刚石大单晶，而且对于揭示天然金刚石的成因机制以及深层次理解地幔乃至地核中的诸多疑难问题具有重要意义。

本项目借助高温高压极端合成条件，采用温度梯度法，通过优选适合硫氢协同掺杂的触媒溶剂和添加剂、调节添加剂的比例、优化合成工艺研制出了具有优异n型半导体功能特性的金刚石大单晶(≥ 5mm)。借助同步辐射X射线、离子束分析、原子隧道扫描技术、显微拉曼和红外光谱等先进测试手段，深入研究了氢与硫在金刚石中的浓度、存在形式、与缺陷间的相互作用机制，重点研究了氢协同掺杂对硫掺杂n型半导体金刚石的电输运调制机制与规律。研究结果表明：氢的傅里叶红外光谱位于2850和2920 cm-1处，而硫缺陷的傅里叶红外光谱位于847 cm-1处。尤为重要的是氢协同掺杂有利于提高金刚石半导体的电导率（10-100倍），结合第一性原理理论模拟计算，氢元素的引入可以有效的调节金刚石的能带结构，进而提高金刚石大单晶的电输运性能。该项目的研究不但制备出了具有优异性能的n型半导体金刚石大单晶，而且对于揭示天然金刚石的成因机制以及深层次理解地幔乃至地核中的诸多疑难问题具有重要意义。