OPTICALLY DETECTED MAGNETIC-RESONANCE STUDIES OF NEUTRON-TRANSMUTATION-DOPED GAP

A direct proof of neutron transmutation doping (NTD) of GaP is presented on the basis of optically detected magnetic resonance (ODMR). GaP:S samples grown by the liquid-encapsulated Czochralski method were irradiated with thermal neutrons and subsequently annealed at 800-degrees-C. In the ODMR experiments the transmuted Ge substitutional on Ga sites was detected. The NTD process was also found to create deep acceptors; these are tentatively identified as associates of gallium vacancies (V(Ga)) and germanium donors on gallium sites (Ge(Ga)). Such identification requires that some of the structural defects (vacancies) created by beta and gamma recoil during transmutation are stabilized by forming V(Ga)-Ge(Ga) complexes.