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back to projects Phonon Modes in InAs/AlSb Superlattices Josh Matsko Illinois State University The InAs/AlSb heterojunction system is a lattice matched semiconductor system with type-II band alignment at the interfaces. This system is attractive to ultra-fast electronic device application due to its high mobility and large conduction-band offset. The superlattice can have two different interfaces: AlAs-like or InSb-like. These interfaces have very different interface roughness, mobility and carrier concentrations. There is experimental evidence showing preferential local arrangements of the interfacial atoms. First principle pseudo-potential calculations indicate that such superlattices with switched layers at the interfaces are more energetically favorable than superlattices with ideal sharp strained interfaces. We theoretically calculate the phonon modes of the InAs/AlSb superlattices using a one-dimensional linear chain model. We compare the interface modes for superlattices with the two different interface structures. We found that there not only are more interface modes in the superlattice with the switched interface layers, but that there also exist bulk modes at the interface, a special feature of this structure.
published: Journal of Undergraduate Research in Physics, VOL 18, #1 |
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