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Exploiting the excited state

Stoneham, AM; (2003) Exploiting the excited state. In: Proceedings of the 22nd International Conference on Defects in Semiconductors. (pp. 48 - 57). ELSEVIER SCIENCE BV Green open access

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Abstract

The major ideas of microelectronics are associated with the electronic ground state, or with states thermally accessible at modest temperatures. Photonics, and many realisations of quantum devices, require excited states. Excited states are the basis of new processing methods for organic and inorganic systems. The natures of excited states can vary enormously and, especially in the wide gap materials, the processes involving excited states are extraordinarily varied. Can these states be controlled or exploited, rather than merely accessed in spectroscopy? Certainly electronic excitation can be used in materials modification, when the ideas of charge localisation and energy localisation are central. The basic processes of energy transfer, energy conversion, energy control, and control of phase exploit wide ranges of excitation intensity, and of spatial and temporal scale. Length scales can span extreme miniaturisation in lithography or quantum dots, mesoscopic scales similar to optical wavelengths, and human scales. Timescales range even more widely, from femtosecond plasmon responses, through picoseconds for self-trapping or pre-plume ablation, to many years for the lifetimes of device components.Semiconductor systems underly two relatively new areas of enormous potential. The first concerns the dynamics of quantum dots, especially the II-VI dots of a few hundred atoms for which confinement is significant, rather than the self-organised III-V dots for which the Coulomb blockade is crucial. The second is quantum information processing based on silicon-compatible quantum gates. In both cases, there are key issues of coherence, whether electronic, vibrational or explicitly quantal. In both cases, conventional intuitive models are insufficient. Yet the emerging picture is optimistic: the combination of small physical size and the variety of available excited states open up major opportunities. (C) 2003 Elsevier B.V. All rights reserved.

Type: Proceedings paper
Title: Exploiting the excited state
Event: 22nd International Conference on Defects in Semiconductors (ICDS-22)
Location: UNIV AARHUS, AARHUS, DENMARK
Dates: 2003-07-28 - 2003-08-01
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.physb.2003.09.232
Publisher version: http://dx.doi.org/10.1016/j.physb.2003.09.232
Language: English
Additional information: Text made available to UCL Discovery by kind permission of Elsevier B.V., 2012
Keywords: Excited state, quantum computing, quantum dots, non-radiative transitions, QUANTUM DOTS, ELECTRONIC EXCITATION, NANOCRYSTALS, SPECTROSCOPY, TEMPERATURE, IRRADIATION, DYNAMICS, SURFACES, SIZE
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/129092
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