T. Worren et al., TRANSFER-MATRIX FORMALISM APPLIED TO ABOVE BARRIER ENERGY-STATES IN STRAINED MULTIPLE-QUANTUM WELLS, Physica scripta. T, T69, 1997, pp. 336-340
We have used the effective mass approximation in a transfer matrix for
malism to describe both confined and unconfined (above barrier) states
in strained InGaAs/GaAs multiple quantum well (MQW) structures. Wa de
duce the transfer matrices for a pseudomorphic MQW structure from the
envelope wavefunction boundary conditions, modified to account for the
discontinuities in the lattice constant. In the calculations we also
take into account the finite width of the cap-layer, and the finite he
ight of the vacuum potential. The potential profiles of the InGaAs/GaA
s MQWs are derived using the calculated positions of the band-edges, t
aken from the model-solid theory. Photoluminescence excitation (PLE) s
pectroscopy has been performed on a series of InGaAs/GaAs MQWs (4-6 pe
riods) at 11 K. We observed excitonic peaks at energies both below and
above the GaAs free exciton. The values of the calculated transition
energies are in good agreement with the experimental peaks.