VACANCY COMPLEXES IN DIAMOND

We review recent data on the annealing of vacancies in types Ia, Ib and IIa diamond. Migration of the vacancy is shown to be mediated through the neutral charge state, with an activation energy of E(m) = 2.3 +/- 0.3 eV. In type Ia and type Ib diamond effectively all the vacancies are in either the neutral V0 or negative V- charge states. An equilibrium is established between V0 and V- during the annealing so that V- is destroyed by first being converted to V0 which is then mobile. On annealing, apparently all the vacancies are eventually trapped at the nitrogen. In electron-irradiated type IaA diamond, neutral vacancies are present at concentrations which are an order of magnitude higher than negative vacancies. Vacancies are preferentially created close to the impurity nitrogen in type IaA diamond.