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11 August 1987 Stability Of Superlattices Under Pressure
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Proceedings Volume 0792, Quantum Well and Superlattice Physics; (1987)
Event: Advances in Semiconductors and Semiconductor Structures, 1987, Bay Point, FL, United States
Under pressure, covalent semiconductors transform to more closely packed metallic (or small band gap) structures, with large reductions in volume ~15-20%. Recent experiments on AlAs/GaAs epitaxial multilayers have revealed that the analogous phase changes in superlattices exhibit several remarkable properties. Depending on layer width, transitions may occur: a) discretely within individual AlAs or GaAs layers, b) collectively within many similarly composed layers, or c) within the entire superlattice as a whole. Furthermore, the zincblende phase of AlAs can be superpressed far above its bulk transition threshold; this superpressing is greater in thinner layers and is limited by the stability of GaAs. These properties reflect the importance of the epitaxial interface for the total energy of a superlattice. A model is presented that considers the energy competition between destroying the interface by producing misfit defects, or preserving it by forming strained layers (in the high pressure phase.) Recent total energy calculations by Martin suggest that, for sufficiently thin layers, one of several novel strained-layer metal/semiconductor structures could be stable at high pressure. Conditions for creating such structures in various materials systems, and for retrieving them metastably at 1 atm., are discussed.
© (1987) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
B. A. Weinstein "Stability Of Superlattices Under Pressure", Proc. SPIE 0792, Quantum Well and Superlattice Physics, (11 August 1987);

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