调控硼硫掺杂比实现金刚石n型转变的研究

n-type conversion of diamond by modulation of B-S codoping ratio

金刚石半导体由于其特殊的机械性能使其在极端环境下有较广的应用前景.虽然通过硼(B)元素掺杂较易得到p型金刚石半导体,但具有优异电学性能的n型半导体却鲜见报道.硼、硫(S)原子因半径及外层电子互补,其协同掺杂易合成p型或n型半导体,但其物理机理尚不清晰.在课题组已有实验报道基础上,借助第一性原理探究了B-S不同比例单掺杂及共掺杂金刚石的形成能、晶体内的存在形式及电子结构,从原子尺度揭示了金刚石由p型向n型半导体转变的阈值掺杂比例.通过实验与理论的对比发现B在晶格内趋向团聚,而过量的S掺杂则发生析出.

Diamond semiconductor has emerged as an important material for potential applications in extreme environment due to the special mechanics.Based on the p-type intrinsic property,the p-type semiconductor with superior performance can be easily synthesized while the n-type diamond synthesis is still a challenge.The diamonds with p-and n-types have been synthesized by codoping B and S atoms due to their complementary atom radii and electrons;however,the physical mechanism is not clear.Based on our experimental results,the formation energies,crystal and electronic structures were calculated for different B and S doping ratios.The band structures give out threshold of the transition from p-to n-type of the diamond.Furthermore,comparing experiment and theory reveals that the doping B atoms tend to agglomerate in the diamond while excess S atoms tend to separate out.