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Current Research Interests of Prof. Iggy McGovern |
The techniques of surface physics are employed to understand semiconductor interface formation. Early work concentrated on metal-semiconductor (i.e. Schottky Barrier) structures; more recent interest is in the organic-inorganic semiconductor heterojunction and the ‘high-k’ dielectric – III-V semiconductor interface. The principal technique employed is photoelectron spectroscopy (PES); this technique is significantly enhanced when coupled with the intense, tunable source of synchrotron radiation. Allied techniques include near edge x-ray absorption fine structure (NEXAFS), x-ray standing wave (XSW) and photoelectron diffraction (PhD).
The group enjoys close collaboration with Dr Tony Cafolla and Prof Greg Hughes ( Dublin City University ), Dr Andy Evans ( University of Aberystwyth ) and Prof Dietz Zahn (Universitaet Chemnitz).
Although the central theme in this research remains the exploitation of synchrotron radiation, increasing use is made of scanning probe techniques and in-house ESCA facilities. Three distinct research areas are actively pursued:
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1. Organic-inorganic semiconductor interface formation
Organic molecules are increasing used in thin film optoelectroic device structures; there is therefore a strong technological interest in the attachment of such molecules to suitable substrates. Inorganic semiconductor surfaces are of particular interest as the organic-inorganic semiconductor arrangement is a hybrid technology that extends the potential of silicon-based technology. Current efforts (in collaboration with Dr Cormac McGuinness) focus on the comparison of photoelectron and x-ray emission/absorption spectroscopies using synchrotron radiation, as well as the effect of ‘beam damage’ on the organic film. The DIODE Project ( Designing Inorganic / Organic DEvices) was an earlier EU-funded Research Training Network involving seven principal collaborators from universities across the European Union. Industrial partners and experts in the US also contributed to the research and training effort. The aim of the project was to understand and develop the bases for new semiconductor devices using combinations of conventional compound semiconductors and organic molecular semiconductors. Visit the DIODE project web pages here!
2. High-k dielectric/InP interface forma tion
Metal oxide semiconductor field effect transistors (MOSFETs) on III-V compound semiconductors have the potential to offer significant advantages over conventional silicon based devices. Higher carrier mobility would lead to faster complementary MOS (CMOS) logic operation while higher breakdown fields would facilitate high power and high temperature applications. The absence of a high-quality gate insulator which replicates the interfacial properties of silicon/silicon dioxide based devices has had a negative impact on the development of III-V based devices. This new project (in collaboration with Prof Greg Hughes) addresses the critical issue of interface formation at the insulator III-V substrate interface which plays a vital role in device applications. Key issues are the growth of suitable dielectric thin films and the chemical/electronic passivation of indium phosphide.
3. Small molecule adsorption on semiconductor surfaces
There is an ongoing interest in the adsorption of small molecules such as H 2O and H 2S on clean, ordered surfaces of silicon, germanium and III-V semiconductors ; the area has a connection with device processing. Key results have been the development of a common model of dissociative adsorption of H and HS on anion and cation sites of Gp III-V (110) surfaces, respectively, and the role of OH in creating a symmetric dimer geometry for Gp IV (001) surfaces.
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research facilities of Iggy McGovern
Postgraduate positions available |
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