Minibands of eigen-state energies of $\hbox {In}_{0.53}\hbox {Ga}_{0.47}\hbox {As}$ multi-quantum wells lattice-matched to InP

Abstract

Lattice-matched $\hbox {In}_{0.53}\hbox {Ga}_{0.47}\hbox {As}$/$\hbox {In}_{0.52}\hbox {Al}_{0.48}\hbox {As}$ multi-quantum wells structures were studied at room temperatures by photocurrent spectroscopy. Step-like structures accentuated by the exciton peaks of interband transitions were observed on the photocurrent spectra. As the step-like structures reflected two-dimensional state density of the multi-quantum wells structures, the interband transitions between electron and heavy hole eigen-states could be identified. Eigen-energies agreed theoretically and experimentally, but the exciton peaks clearly appeared at smaller quantum numbers and did not appear at larger quantum number. If it is based on our calculation result, both side hems of the wave function appear in the barrier layers and are connected to ones of the neighbors, which are affected against larger quantum number. Then the degeneracy melts and the higher eigen-states split to form a miniband having a width, and it might be that the exciton peak becomes inconspicuous.