金刚石(001)面在Cu多种覆盖度下的稳定构型与电子特性

摘要/Abstract

摘要： 金刚石表面的电子特性很容易受到其表面覆盖物的影响,而目前表面稳定、性能优良的表面覆盖层依然处于研究与寻找中。本文研究的过渡金属Cu不仅在半导体微加工中被广泛使用,更由于过渡金属Cu与金刚石都具有优异的散热性能,因此Cu覆盖金刚石已经超出寻常电极使用的意义,其金属-半导体结构更具有表面修饰剪裁电子特性的功能。文中通过使用密度泛函模拟方法,研究了Cu的不同覆盖度(0.25 ML、0.5 ML和1 ML)下金刚石(001)表面的单原子吸附能、稳定构型以及稳定体系的能带结构特性。结果表明,各种覆盖度下的Cu原子在金刚石(001)表面具有较稳定的表面吸附构型,并且过渡金属Cu的覆盖使得金刚石(001)表面产生了约为-0.5~-0.3 eV的负电子亲和势,肖特基势垒高度约为-0.16~0.04 eV,这些理论结果与实验结果基本一致。因此过渡金属Cu作为表面覆盖层在金刚石基电子发射器方面具有重要的应用价值。

关键词: 金刚石表面, 覆盖度, 负电子亲和势, 电子结构, 第一性原理计算

Abstract: The electronic properties of diamond surface are easily affected by its surface covered layer, like species, concentration and structure of the surface covered layer. At present, the surface covered layer with stable configuration and excellent performance is still under study. In our work, transition metal (Cu) is used as the surface covered layer. The transition metal (Cu) studied in this paper is not only widely used in semiconductor micro-fabrication, but also has excellent performance of heat dissipation, which is very similar with diamond on this point. Moreover, ultrathin layer of Cu has recently been deposited on diamond as an epitaxy, where the thermally stable and characteristic of negative electron affinity were found. As a result, Cu-covered diamonds have become more important than ordinary electrodes, and it is very important for the Cu-diamond structure to modify and tailor electronic properties of diamond (001) surface. In this paper, the adsorption energy, stable configuration and energy band structure of diamond (001) surface covered by transition metal (Cu) with different coverage (0.25 ML, 0.5 ML and 1 ML) have been studied by density functional simulation. The results show that Cu as a surface coating can induce a negative electron affinity about -0.5 eV to -0.3 eV and a Schottky barrier height(Φ_BH) of -0.16 eV to 0.04 eV, which is in good agreement with the experimental data. At the same time, the diamond (001) surface covered by the transition metal (Cu) with various coverage has also shown the stable configurations. Therefore, all these results suggest that Cu as a surface coating have an important application in diamond-based electron emission device.

Key words: diamond surface, coverage, negative electron affinity, electronic structure, fist-principle calculation

中图分类号:

TQ163
TB306

吴孔平, 张冷, 王丹蓓, 肖柳, 陈泽龙, 张靖晨, 张鹏展, 刘飞, 汤琨, 叶建东, 顾书林. 金刚石(001)面在Cu多种覆盖度下的稳定构型与电子特性[J]. 人工晶体学报, 2021, 50(9): 1640-1647.

WU Kongping, ZHANG Leng, WANG Danbei, XIAO Liu, CHEN Zelong, ZHANG Jingchen, ZHANG Pengzhan, LIU Fei, TANG Kun, YE Jiandong, GU Shulin. Stable Configurations of Diamond (001) Surface Covered by Cu with Various Coverages and Their Electronic Properties[J]. JOURNAL OF SYNTHETIC CRYSTALS, 2021, 50(9): 1640-1647.

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