We report a determination of band offsets in strained-layer ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$-GaAs quantum wells lattice-matched to GaAs. Using a light-scattering method, we find a large offset for the averaged valence bands, which extrapolates to $\Delta E_{v,\mathrm{av}}=0.49\mathrm{}$ eV in the InAs-GaAs system. This vlaue contradicts previous experimental determinations but agrees with predictions of theories that consider charge-transfer effects at the interface. It follows from some of these theories that $\Delta E_{v,\mathrm{av}}$ has a surprisingly strong uniaxial strain dependence, a fact that is consistent with our experimental result. Our light-scattering experiment leads to a new band structure for the ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$-GaAs system lattice-matched to GaAs in which the ground state for light holes is localized in the ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{As}$ layers. This conclusion is supported by photoluminescence excitation experiments.

• Received 22 May 1987

DOI:https://doi.org/10.1103/PhysRevB.36.8165