Study of the valence band offsets between InAs and InAs 1-x Sb x alloys

摘要: 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 LWIR) laser photodetector applications, but SLs not as thoroughly investigated. Therefore, valence band offset between InAs InAs/InAs1-xSbx, critical parameter necessary predict SL bandgap, must be further examined produce devices operational at MWIR LWIR wavelengths. The effective bandgap energies of with x = 0.28 - 0.40 designed using three-band envelope function approximation model. Multiple 0.5 μm-thick samples are grown by molecular beam epitaxy substrates. Structural characterization x-ray diffraction atomic force microscopy reveals excellent crystalline properties zero-order peak full-width-half-maximums 30 and 40 arcsec 20 μm2 area root-mean-square roughnesses 1.6 - 2.7 A. Photoluminescence (PL) spectra of these cover 5 8 μm, is obtained fitting PL peaks to the calculated values. bowing in found depend initial InAs/InSb offset and changes linearly CEv_bowing 1.58x 0.62 eV when an parameter 0.67 is assumed. A fractional offset, Qv ΔEv/ΔEg, 1.75 ± 0.03 determined practically constant the composition range studied.