Enhancement of long lifetime lines in photoluminescence from Si:In

We report a sample treatment technique which increases by a factor of between 50 and 10,000 the intensity of the long-lived P, Q and R lines previously observed in photoluminescence spectra of Si:In. The intensity of the indium bound exciton line is essentially unaffected. By studying these lines as a function of temperature, excitation density and delay time after pulsed excitation, we conclude that all three transitions are associated with the same isoelectronic binding center; contrary to prior assertions.