TIME-RESOLVED OPTICALLY DETECTED MAGNETIC-RESONANCE OF LUMINESCENCE FROM SI/SI1-XGEX SUPERLATTICES

Time-resolved optically detected magnetic resonance (TR-ODMR) experiments have been performed on Si/Si1-xGex superlattices grown by molecular beam epitaxy (MBE) on (001) Si. These structures exhibit a single, broad (full width at half-maximum amplitude approximately 70 meV) photoluminescence (PL) band with peak energy 100 meV below the expected band gap. Fast (tau less-than-or-equal-to 5 mus) and slow (tau congruent-to 20 As) processes have been separated with the TR-ODMR. The slow resonances are new and provide more detailed information on the nature of the recombination. These features are tentatively assigned to Ge-rich regions in the SiGe layers based on the resonance parameters and the faster spin-lattice relaxation.