Three-dimensional electron-positron momentum distribution of O 3+-irradiated 6H SiC using two positron spectroscopy techniques simultaneously

Abstract

A three-dimensional (3D) positron annihilation spectroscopy system (3DPASS) capable of determining 3D electron-positron (e--e+) momentum densities from measurements of deviations from co-linearity and energies of photons from e--e+ annihilation events was employed to examine the effects of O-atom defects in 6H SiC. Three-dimensional momentum datasets were determined for 6H SiC irradiated with 24 MeV O 3+ ions. Angular correlation of annihilation radiation (ACAR) and coincidence Doppler-broadening of annihilation radiation (CDBAR) analyses are presented. In addition, a novel technique is illustrated for analyzing 3D momentum datasets in which the parallel momentum component, p|| (obtained from the CDBAR measurement) is selected for annihilation events that possess a particular perpendicular momentum component, p- observed in the 2D ACAR spectrum.