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Semiconductor Physics Research GroupThe Semiconductor Physics Group WWW pages are at http://newton.ex.ac.uk/research/semiconductors/.
Semiconductor physics has been amongst the most exciting and rapidly advancing areas of physics in the past decade. Enormous leaps have been made in our understanding of semiconductor processes, and in the ways we can make semiconductors. Engineering of the electronic properties of materials can now be achieved at the atomic level, and totally new phenomena have resulted. The quantum Hall effect and the quantum-confined Stark effect are just two examples of new and exciting physics which have emerged as a result of activity in this area. The great potential of the new phenomena for optical and electronic devices has led to a high demand for scientists with research experience in semiconductor physics. This means that job prospects in the international market are excellent for people with a PhD in semiconductor physics.
The Semiconductor Physics Group at Exeter is concerned with both the experimental and theoretical properties of semiconductors. Started in 1985 it has brought together a complement of 8 senior staff, 4 experimental and 4 theoretical. Together with postdoctoral workers and research students it comprises over 27 people. The group has a high level of research activity and has attracted substantial support from the University, EPSRC and elsewhere. Close co-operation is maintained with external groups in Universities, Government Establishments and Industry. The present activities and facilities are outlined in more detail below.
Experimental ProjectsExperimental studies in the Semiconductor Physics Group concentrate on two main areas, each of considerable interest from both fundamental and applied points of view: the effects of electron-electron interactions on the properties of electron systems of reduced dimensionality, and quantum interference and mesoscopic effects in sub-micron semiconductor structures near the metal-insulator transition. Our study of low dimensional electron systems has led to the observation of dramatic effects on the conduction and optical response of high mobility electron systems at very low temperatures and high magnetic fields, caused by electron-electron interactions. The group has developed considerable expertise in optical spectroscopy thermodynamic measurements and in electrical conductivity measurements which forms the basis for several of the projects described below. The list is not exhaustive, but is intended to give some idea of the nature of the experimental work on offer to students interested in a PhD in experimental semiconductor physics:
Experimental FacilitiesThe group is rapidly expanding its own experimental facilities as well as drawing upon those provided elsewhere. The group's own laboratories include a range of equipment for optical and transport measurements. Our optical laboratories are equipped with argon-ion pumped titanium sapphire laser, providing tunable excitation sources near the GaAs bandgap. In addition, state-of-the-art detection systems on our various spectrometers enable very weak signals to be detected. Supply of specimens grown by Molecular Beam Epitaxy is guaranteed under EPSRC contracts and is further facilitated by our collaborations with various universities and electronics companies in the U K and worldwide.
Our laboratories are equipped with cryostats covering the range of temperatures from 20 mK to room temperature, and superconducting solenoid magnets providing fields of up to 17 T. Optical access is also available in these systems using optical fibres or windows. High-quality signal recovery apparatus is used in computer-controlled experiments on electronic systems confined to two or fewer dimensions. Appropriate diagnostic and measuring equipment is available, together with various group facilities for specimen handling. The group has a clean room for sample fabrication, with facilities for optical lithography, etching and annealing contacts.
The laboratories are supported by the Department's very well staffed Mechanical and Electronics Workshops which are used to undertake tasks ranging from the construction of complete helium dilution refrigerators to microprocessor-controlled monitoring apparatus. The Department also runs its own helium and nitrogen liquefiers.
Theoretical StudiesTheoretical work within the Group covers a wide range of topics in condensed matter physics, using both formal and computational techniques, and has an international reputation. We have major efforts in the areas of many body theory, the electronic properties of surfaces, heterojunction systems, low-dimensional semiconducting structures, and the electronic and mechanical properties of non-metallic solids. Close co-operation between the experimental and theoretical group members is maintained by regular informal seminar meetings and joint research programs.
The development of computational power and sophisticated analytical formulations has increased the physicists' ability to treat real systems and relate theory to experimental developments. At Exeter we have developed a whole range of techniques, which are amongst the most powerful currently available anywhere, for the investigation of complex solid state problems.
Computational FacilitiesThe theoretical group has its own dedicated cluster of Unix workstations and is part of a consortium at the University which has recently acquired a large supercomputer. The group also has access to national supercomputers, Cray YMP8 at the Rutherford Laboratory and Fijutsu at University of Manchester Computer Centre, as well as a set of SGI machines provided by the University's Computer Unit.
Up to Physics Research Groups at Exeter.