Electron-beam-induced dissociation of (B,D) complexes in diamond mediated by multiple vibrational excitations

Abstract

In this work, we investigate the dissociation kinetics of boron-deuterium (B,D) pairs under an electron beam (e-beam) in diamond. This technique is of high interest as it would enable the fabrication of electrically isolating/conductive pathways in diamond using e-beam direct writing. Cathodoluminescence is used to follow the concentration of boron acceptors, via the bound and free-exciton recombinations. We observe that (i) the dissociation rate critically depends on the e-beam excitation current (ii) the dissociation of (B,D) pairs is more efficient at 10 K than at 100 K. This demonstrates that a multiple vibrational excitation is involved in the dissociation of (B,D) complexes in diamond under e-beam. In the theoretical framework of a vibrational dissociation mechanism of hydrogen-related complexes, an analysis of the experimental data indicates that the injection of minority carriers lowers the energy of the dissociation barrier from 2.5 to 0.7 eV.