Semiconductor Heterojunction Engineering
MINNESOTA UNIV MINNEAPOLIS
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The purpose of the research was to explore the microscopic mechanisms that determine interface parameters in semiconductor heterojunctions and develop new methods to tune such interface parameters. We found that while in most isovalent heterojunctions the interface parameters are primarily dependent on the properties of the bulk semiconductor constituents, in heterovalent heterojunctions with polar orientation the interface parameters can be controlled my modifying the local interface environment. Changes in the relative abundance of the different elemental constituents at the interface, for example, produced unprecedented changes in the band alignment across the interface. Even in isovalent heterojunctions, we succeeded in modifying the band offsets through fabrication of thin heterovalent interface layers within the interface region. The resulting system of inequivalent, neutral heterovalent interfaces can be used to control the band alignment across the overall structure. Among the systems of interest for which we have obtained unprecedented modifications of the interface parameters, we mention AlAsGaAs, CdTeGaAs, and ZnSeGaAs heterostructures, all of which have important applications in optoelectronic devices ranging from lasers to light emitting diodes and photodetectors.
- Electrical and Electronic Equipment
- Lasers and Masers
- Atomic and Molecular Physics and Spectroscopy
- Solid State Physics