Thermally stimulated luminescence and conductivity in boron-doped diamonds

Thermally stimulated luminescence and conductivity measurements have been performed in natural and synthetic semiconducting diamonds, in the temperature range 12-350 K, after excitation, near liquid-helium or liquid-nitrogen temperatures, with uv light, x-ray, 150-keV, and 0.5-MeV electrons. The glow curves observed in synthetic diamonds are similar to the glow curves obtained previously in natural diamonds. Two of the peaks which are reported have only been previously observed in types-I and -$\Pi a$ diamonds. Conductivity measurements exhibit stages at 160, 230, and 340 K which correlate with thermoluminescence peaks. An additional stage at 50 K is observed after 0.5-MeV electron irradiation. The concentrations of the traps in these different stages have been deduced. The stage at 50 K is shown to be associated with a donor level situated at 0.02 eV below the conduction band.