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

Nanoscale In0.53Ga0.47As/In0.52Al0.48As multiquantum wells structures were studied by photocurrent spectroscopy. Photocurrent spectra showed clear ste plike structures accentuated by exciton peaks. Many interband transitions w ere 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 estimate d in a square potential well. New estimation methods of valence band parame ters, 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 th e valence band offset were 0.38m(0) and 0.22 eV. (C) 1999 American Institut e of Physics. [S0021-8979(99)00108-5].