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Spatially direct and indirect photoluminescence from InAs/AlSb heterostructures

Räumlich direkte und indirekte Photolumineszenz von InAs/AlSb Heterostrukturen
: Fuchs, F.; Schmitz, J.; Ralston, J.D.; Koidl, P.


Physical Review. B 49 (1994), Nr.19, S.13638-13642
ISSN: 0163-1829
ISSN: 1098-0121
ISSN: 0556-2805
Fraunhofer IAF ()
InAs; photoluminescence; Photolumineszenz; Typ II Heterostruktur; type II heterostructure

We present a Fourier-transform photoluminescence study of InAs/AlSb type-II heterostructures, spanning the midinfrared 1-12 mym wavelength range. The investigated samples consist of single and double quantum wells, grown on GaAs substrates by molecular-beam epitaxy, with different buffer-layer structures for strain accommodation. The photoluminescence intensity is found to be very sensitive to detailed structure of the underlying buffer sequence. The use of a GaSb buffer or a GaSb/AlSb superlattice in the buffer gives rise to an additional radiative-recombination channel in the near infrared, which competes with radiative recombination in the InAs quantum wells at longer wavelengths. Variations in the spectra observed under visible and infrared excitation provide evidence that the recently observed persistent photo effect is governed by hole capture in the GaSb layers in the buffer sequence. Furthermore, very wide quantum wells (100 and 200 nm) show spatially indirect photoluminescence , providing insight into the nature of the transition from the bulklike semiconductor to the type-II heterostructure.