Sulfur: A potential donor in diamond

We performed first-principle calculations of substitutional sulfur in diamo nd, in the neutral (S-0) and charged states. The energy levels induced by s ulfur in diamond are calculated to be 0.15 and 0.5 eV from the bottom of th e conduction band, for S-0 and the singly ionized state S+, respectively. T he formation energy for the neutral state of sulfur is found to be 7.2 eV, lower than that of phosphorus in diamond. The most likely state of sulfur i n diamond is found to be the doubly ionized state S++, which cannot act as a donor. However, a small fraction of sulfur can be found in the singly ion ized state S+, which can donate an electron for conduction at reasonable te mperatures. (C) 2000 American Institute of Physics. [S0003-6951(00)03932-2] .