The optical absorption of the 3H center was studied via the isochronal annealing, at 370 to 620K, of samples which had been irradiated with electrons or neutrons. Undoped (substitutional N less than 1ppm) and B-doped (few ppm of B) chemical vapour deposited films were produced by using a microwave plasma technique. It was found that, in undoped diamond, the increase in 3H absorption at an annealing temperature of 620K was associated with an increase in absorption of the negatively charged vacancy (V-). Meanwhile, the absorption of the neutral vacancy (V0) diminished. In B-doped diamond, the absorption of both the 3H and V0 centers increased; and this occurred at the lower annealing temperature of 470K. The observed trends could be explained by charge transfers between the 3H and vacancy centers. This led to the conclusion that the (3H)0 center was a donor, and that the 2.462eV absorption line belonged to the center in the positively charged state, (3H)+.

Experimental Evidence for Charge State of 3H Defect in Diamond. I.I.Vlasov, R.A.Khmelnitskii, A.V.Khomich, V.G.Ralchenko, W.Wenseleers, E.Goovaerts: Physica Status Solidi A, 2003, 199[1], 103-7