Structural, Energetic, and Electronic Properties of H-Interstitial in C-Monovacancy: A First-Principles Density Functional Theory

Abstract

We discover a unique structural-modified diamond that exhibits similar symmetry and band gap energy to that of the pure diamond. We study a complex carbon-vacancy-hydrogen in the diamond using the density-functional-theory method. The defective models are created by adding H-interstitial (Hi, where i = 1, 2, 3 and 4) in the 3D diamond C-monovacancy. The result shows that carbon-vacancy-hydrogen defects significantly decreased the symmetry from Td to C2V. Likewise, the volumetric size of the systems is widening up to 48.70 %, while the optimized band gap energies are narrowing. Additional states appeared in the C-monovacancy, H1-V, H2-V, and H3-V systems which further improved electron mobility. The Hi compensates the C-monovacancy which further serves as a deep donor. Interestingly, H4-V exhibits similar symmetry and band gap energy to that of the pure diamond, but its volumetric size is 48.70 % wider.