THERMAL ANNEALING OF NATURAL SEMICONDUCTING DIAMOND

A number of natural semiconducting diamonds were subjected to thermal annealings in the temperature range 500-2500°C. The following parameters were determined as a function of annealing:- the resistivity (ρ{variant}), the Hall mobility (μH) and the concentrations of acceptor levels (Na), donor levels (Nd) and charge carriers (p). Their annealing behaviour was as follows:- Na and μH remained unchanged, Nd and ρ{variant} decreased and p increased. A correlation was observed between changes in Nd, p and ρ{variant}. The annealing data were analysed by plotting their so-called characteristic activation energy spectra. The range of activation energies over which changes could be produced varied from small values to about 9 eV. The shapes of the spectra revealed a number of distinct annealing processes. The annealing was found to be strongly specimen-dependent. © 1969.