A BRILLOUIN LIGHT-SCATTERING STUDY OF THE ELASTIC PROPERTIES OF IN0.5GA0.5AS INP SUPERLATTICES GROWN BY CHEMICAL BEAM EPITAXY/

The Brillouin light scattering technique has been exploited for invest igating the elastic properties of INxGa1-As-x/InP superlattices, with x = 0.5 and a total thickness of several hundreds of nanometres. These superlattices have been grown by chemical beam epitaxy and are close to being lattice matched to the InP substrates. The frequency position in the Brillouin spectra of the Rayleigh surface wave, and of the tra nsverse and longitudinal thresholds for two different propagation geom etries, enabled us to determine the three effective elastic constants of the superlattices. A comparison between these experimental values a nd those expected from calculation based on the properties of InP and InGaAs single films shows that interface effects do not play any signi ficant role in modifying the elastic properties of InGaAs/InP heterost ructures.