Infra-red absorption measurements showed that high-resistivity material, which had been grown by means of metalorganic vapor-phase epitaxy at 500C and had been doped using CCl4, contained relatively high concentrations (about 3 x 1018/cm3) of isolated CP acceptors and H-CP pairs. These centers gave rise to localized vibrational modes at 546.9/cm (CP) or at 2703.3, 521.1 and 413.5/cm (H-CP). A sharp weak line, which was also situated at 546.9/cm, was attributed to a much lower concentration of CIn donors. It was concluded that doping introduced CP acceptors that over-compensated grown-in donors, while complete compensation resulted from the formation of H-CP pairs.

Vibrational modes of carbon acceptors and hydrogen-carbon pairs in semi-insulating InP B.R.Davidson, R.C.Newman, C.C.Button: Physical Review B, 1998, 58[23], 15609-13