Photocurrent spectroscopy and study of subband parameters for heavy holes in nanoscale In0.53Ga0.47As/In0.52Al0.48As multiquantum well structures

Abstract

Nanoscale In0.53Ga0.47As/In0.52Al0.48As multiquantum wells structures were studied by photocurrent spectroscopy. Photocurrent spectra showed clear steplike structures accentuated by exciton peaks. Many interband transitions were assigned from the spectral structure. As peaks of forbidden transitions, which appeared in large reverse bias voltages, were extrapolated to zero bias voltage on the photocurrent spectra, transition energies were estimated in a square potential well. New estimation methods of valence band parameters, heavy hole effective mass and valence band offset, were derived from a saturation of the heavy hole subband in the valence potential well, using the envelope function model in the effective mass approximation. The heavy hole effective mass in a direction normal to the quantum well plane and the valence band offset were 0.38m0 and 0.22 eV.