First-Principles Calculation to N-type Beryllium Related Co-doping and Beryllium Doping in Diamond.

The Beryllium-doped (Be-doped) diamond and Beryllium related (Be-X) co-doped diamond have been carefully investigated by the density functional theory (DFT) to explore the possibility to achieve effective and shallow n-type doping in diamond. Although the ionization energy and formation energy of interstitial/substitutional Be-doped diamond is not ideal, the introduction of Be-related co-doping techniques (Be-N/O/S) greatly improves the electrical properties in diamonds. We found, for the first time, n-type diamond doping can be realized in Be-N, Be-O and Be-S co-doped systems, among which Be-N 3 has the best performance. Be-N3 has the advantages of low ionization energy (0.25 eV), low formation energy (−1.59 eV), and direct bandgap. The N-2p states play a crucial role in the conduction band edge of Be-N3 co-doped diamond. Hence, the Be-N 3 could be expected to become a promising alternative for N-type shallow doping in diamond.