CATHODOLUMINESCENCE AND ELECTROLUMINESCENCE IN ION-IMPLANTED TYPE-II DIAMONDS

Two type IIa diamonds were doped by cold target ion implantation followed by rapid annealing (the CIRA process). In one diamond, boron ions were used to effect a partially compensated p-type layer, and in the other diamond an equivalent fluence of carbon ions was used to create the same density of donors without activating any acceptors. Although the donor-acceptor density increased drastically in the first diamond, its band A cathodoluminescence did not shift to higher photon energies, indicating that this band may not be related to donor-acceptor pair recombination. In the second diamond a broad band developed in the UV, which peaked at approximately 4 eV. This same band could be generated by electroluminescence of a diode in which the n-type region had been formed by CIRA carbon-ion implantation. The properties of this UV luminescence band provide strong evidence that it is generated by electron transitions from the conduction band to the ground states of the donors caused by the implantation procedure.