Migration of nitrogen in electron-irradiated type Ib diamond

Abstract

The 1.945 eV optical centre is produced in type Ib diamond by radiation damage and annealing at approximately 800 degrees C. The author reports that H3 (2.463 eV) centres, characteristic of irradiated and annealed type Ia diamond, have been created by heating an irradiated type Ib diamond to temperatures where nitrogen aggregation occurs. This observation strongly supports the models recently proposed for the H3 and 1.945 eV centres. The rate of nitrogen aggregation appears to be considerably faster than that reported previously for unirradiated samples.