N-type diamond semiconductor induced by co-doping selenium and boron

First-principles calculations were conducted to study the possibility of using selenium (Se)-doped and Se–X [X = boron (B), nitrogen (N), oxygen (O), fluorine (F)] co-doped diamonds as n-type diamond semiconductors. The calculation results indicate that Se-doped diamond and Se–B co-doped diamond exhibit n-type semiconductor characteristics. Moreover, they have direct band gaps of 3.146 eV and 3.425 eV, respectively. However, the preparation of Se-doped diamond through experiments is difficult because of its high defect formation energy of 14.476 eV. Meanwhile, obtaining Se–N, Se–O, and Se–F co-doped diamonds through experiments is challenging because of their high defect formation energies of 15.151, 16.506 and 17.995 eV, respectively. Fortunately, Se–B co-doped diamond with a defect formation energy of 8.834 eV can be prepared by experiment. The electron effective mass of Se–B co-doped diamond in [0 1 0] direction is 0.773 m0, which is smaller than the electron effective mass of diamond in [0 1 0] direction (1.591 m0). It means doping Se-B can improve the electron mobility of diamond. The ionization energy of Se–B co-doped diamond is 0.428 eV, which indicates that the Se–B impurity generates a shallow donor level. It can conclude that Se–B co-doped diamond is an available n-type diamond semiconductor.