Determination of Conduction Band Offsets in Type-II In0.27Ga0.73Sb/ InxAl1-xAsySb1-y Heterostructures Grown by Molecular Beam Epitaxy
Abstract
Low-temperature photoluminescence (PL) has been performed on a set of specially designed In0.27Ga0.73Sb/ InxAl1 xAsySb1 y multiple quantum well (MQW) heterostructures grown by molecular beam epitaxy in order to provide a measure of the conduction band offsets in this material system. These alloys are of interest for the development of high-speed heterojunction bipolar transistors (HBTs) that show promise for operation at lower power dissipation than in GaAs- and InP-based HBTs. Excitation power studies revealed evidence for strong electron-hole recombination at 0.56 eV within the InGaSb layers of the type-I MQW structure with (x=0.52, y=0.25), while several weaker indirect transitions involving electrons in the InxAl1 xAsySb1 y and holes in the InGaSb layers were observed between 0.38 and 0.53 eV from the nominally type-II MQW samples with (x, y)=(0.67, 0/390 and (0.69,0.41). Neglecting small corrections (~15 meV) due to the electron and hole confinement energies, we estimate conduction band offsets of ~120 150 meV in these type-II structures. The general trends of the PL features as a function of excitation power have been reproduced from modeling of the quantum well electron and hole subband energies, including effects due to band bending at the heterointerfaces.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2006
- Accession Number
- ADA574235
Entities
People
- Benjamin V. Shanabrook
- Evan R. Glaser
- J. G. Tischler
- Richard Magno
Organizations
- United States Naval Research Laboratory