The use of modern epitaxy techniques, such as MBE, allows modification of crystal structures on an atomic scale. Since most of the fundamental properties of semiconductor structures can be traced back to the periodic structures of the atoms, modifying the symmetry of these structures will lead to features designed for various purposes. Consequently, advanced optoelectronic devices, such as light emitting diodes and laser diodes are usually fabricated with epitaxially grown structures.
The degree of control over the structures also provides systems for exploring fundamental phenomena in reduced dimensions, such as 2-dimensional electron gas. Meanwhile, the growth itself involves nonequilibrium thermodynamic processes, which can be used for improving our knowledge in this area. A wide variety of problems involving surfaces and interfaces can also be studied in an MBE system.
Although he does not define usefulness purely by commercial applications, he strongly believes that semiconductor physics should be closely connected to future technologies. His recent studies of optoelectronic devices include blue-green laser structures, optical modulators using type-II heterostructures, and design and fabrication of a new type of semiconductor lasers in the form of an equilateral triangle (patent pending).
Current projects include the studies of a new type of electronics, called spintronics , which just began its research stage. Another focus of the research activities involves semiconductor nanostructures, in the form of quantum dots and quantum-dot-molecules . In an attempt to further extend the possibilities of semiconductor applications, flexible crystal structures have been successfully added as a new member to the family of semiconductor structures. It was demonstrated that single crystal structuress can bend without breaking, and thus can be considered for new device applications, as well as alternatives for many existing device configurations (such as optical wave guides, panel displays and solar cells).
The MBE effort is closely connected to a wide range of interdisciplinary projects involving other faculty members in the Departments of Physics (Professors Petrou , McCombe , Weinstein , and Kao ), Chemistry (Professor Gardella ), Electrical Engineering (Professor Anderson ), and Chemical Engineering (Professor Mountziaris ), covering structural, optical, and transport studies, as well as device fabrications. The students in his group also spend as much as half of their time working with other research groups. It is his hope to establish a procedure so that his students will gain substantial experience in other laboratories, while providing training in the MBE lab to students from other groups.
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