Coupled ultrathin InAs layers in GaAs as a tool for the determination of band offsets

We have determined the band offsets at the highly strained InAs/GaAs heterointerface by photoluminescence excitation (PLE) measurements of the symmetric and antisymmetric states in two coupled ultrathin InAs layers embedded in a GaAs matrix. The conduction band offset ¿Eccould be separated from the valence band offsets, since in a 32 monolayer (ML) barrier sample, the splitting between the heavy-hole exciton transitions is solely determined by ¿Ec. Knowing ¿Ec, the heavy-hole (hh) and light-hole (lh) band offsets ¿Ehhand ¿Elhcould subsequently be determined from the coupling-induced shift and splitting in samples with a 16, 8 and 4 ML barrier. We find a conduction band offset of 535 meV, a conduction band offset ratio ofQc= 0.58 and a strain induced splitting between the hh and lh subbands of 160 meV.