The spectra of nuclear resonances provide a powerful microscopic probe of condensed matter, yet nuclear magnetic resonance (NMR) techniques have net so far been used to study semiconductor heterostructures. That is because only a tiny fraction of all the nuclei lie in the region of interest, and conventional NMR cannot distinguish these. We report the first observation of optically detected NMR (ODNMR) of spatially selected nuclei in a semiconductor quantum well using an optical pumping technique which has the sensitivity and selectivity to overcome the limitations of conventional NMR. The sample is a 200-Å thick single quantum well made p-type by applied electrical bias with a degenerate hole population of 1011 cm−2. The spectrum contains resonances corresponding to the three isotopes which make up the lattice: 69Ga, 71Ga. and 75As. It differs strikingly from that reported for bulk GaAs1 in that there is a 60(7)-kHz quadrupole splitting of the 75As resonance. shown In Fig. 1, which we attribute to the residual strain present in the GaAs layer.
© 1989 Optical Society of AmericaPDF Article