RAMAN-SCATTERING OF INSB QUANTUM DOTS GROWN ON INP SUBSTRATES

In this paper we present the Raman scattering of self-assembled InSb d ots grown on (001) oriented InP substrates, The samples were grown by pulsed molecular beam epitaxy mode. Two types of samples have been inv estigated. In one type the InSb dots were capped with 200 monolayers o f InP; in the other type no capping was deposited after the InSb dot f ormation. We observe two peaks in the Raman spectra of the uncapped do t, while only one peak is observed in the Raman spectra of the capped dots. In the case of the uncapped dots the peaks are attributed to LO- like and TO-like vibration of completely relaxed InSb dots, in agreeme nt with high resolution transmission electron microscopy photographs. The Raman spectra of the capped dot suggest a different strain stare i n the dot due to the capping layer. (C) 1997 American Institute of Phy sics.