H-2-ASTERISK DEFECT IN CRYSTALLINE SILICON

Detailed infrared studies have been carried out on proton- and deuteron-implanted Si. A dominant trigonal defect involving a pair of inequivalent hydrogen atoms has been identified, with local modes at 2061.5, 1838.3, 1599. 1, and 817.2 cm-1. The structure, the local modes, and the isotopic shifts of the H-2* defect have been calculated using ab initio pseudopotential cluster theory. The structure is consistent with channeling and uniaxial stress experiments. The calculated frequencies and isotopic shifts are in close agreement with those observed.