Photoluminescence of InAs/AlSb single quantum wells

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Abstract
A photoluminescence study of InAs/AlSb single quantum well structures with a width varying between 20 and 5 nm is presented. Using Fourier-transform spectroscopy, the spatially indirect radiative recombination is observed. Excitation of the photoluminescence at 1.32 μm instead of excitation in the visible leads to broadening and blueshifting of the spectra. This behavior is explained by a photoinduced increase of the electron concentration. The optically induced blueshift of the low energy onset of the spectra is attributed to screening of an acceptor level in the AlSb barrier near the InAs/AlSb interface, located about 80 meV above the AlSb valence band maximum. The blueshift of the high energy of the luminescence spectra is limited to a transition energy of 420 meV, providing evidence for the existence of a deep level in the AlSb barriers.