20 January 2012 Study of the valence band offsets between InAs and InAs1-xSbx alloys
Author Affiliations +
InAs/InAs1-xSbx strain-balanced superlattices (SLs) on GaSb are a viable alternative to the well-studied InAs/Ga1-xInxSb SLs for mid- and long-wavelength infrared (MWIR and LWIR) laser and photodetector applications, but the InAs/InAs1-xSbx SLs are not as thoroughly investigated. Therefore, the valence band offset between InAs and InAs/InAs1-xSbx, a critical parameter necessary to predict the SL bandgap, must be further examined to produce InAs/InAs1-xSbx SLs for devices operational at MWIR and LWIR wavelengths. The effective bandgap energies of InAs/InAs1-xSbx SLs with x = 0.28 - 0.40 are designed using a three-band envelope function approximation model. Multiple 0.5 μm-thick SL samples are grown by molecular beam epitaxy on GaSb substrates. Structural characterization using x-ray diffraction and atomic force microscopy reveals excellent crystalline properties with SL zero-order peak full-width-half-maximums between 30 and 40 arcsec and 20 x 20 μm2 area root-mean-square roughnesses of 1.6 - 2.7 A. Photoluminescence (PL) spectra of these samples cover 5 to 8 μm, and the band offset between InAs and InAs/InAs1-xSbx is obtained by fitting the PL peaks to the calculated values. The bowing in the valence band is found to depend on the initial InAs/InSb valence band offset and changes linearly with x as CEv_bowing = 1.58x - 0.62 eV when an InAs/InAs1-xSbx bandgap bowing parameter of 0.67 eV is assumed. A fractional valence band offset, Qv = ΔEv/ΔEg, of 1.75 ± 0.03 is determined and is practically constant in the composition range studied.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Elizabeth H. Steenbergen, Oray O. Cellek, Dmitri Lubyshev, Yueming Qiu, Joel M. Fastenau, Amy W. K. Liu, Yong-Hang Zhang, "Study of the valence band offsets between InAs and InAs1-xSbx alloys", Proc. SPIE 8268, Quantum Sensing and Nanophotonic Devices IX, 82680K (20 January 2012); doi: 10.1117/12.907101; https://doi.org/10.1117/12.907101

Back to Top