PREFACE

Abstract

Extended Defects in Semiconductors 2000 was a conference in the tradition of earlier EDS conferences (such as EDS'98 in Jaszowiec, Poland and EDS'96 in Hyeres, France), but with an increased emphasis on computer modelling. Many themes had their roots in these earlier very successful meetings.An excellent historical introduction to the area was given by Professor Wolfgang Schröter. It was in the first half of the last century that dislocations were proposed; they were observed directly in the middle of the century and then the advent of the semiconductor industry drove the detailed characterization and modelling of dislocations in semiconductors that have brought us to our present situation. Powerful techniques such as electron microscopy, deep level transient spectroscopy, photo- and cathodo-luminescence and electron spin resonance are being applied to a broad range of materials of ever improving purity.The industrial drive has intensified and knowledge of extended defects is recognized as the key to controlling material properties in devices of shrinking size but increasing dimensionality. It is also believed that understanding extended defects in chemically and structurally simple covalent materials could help unlock the mysteries of plasticity and brittleness in the more complex ceramics and minerals. We are grateful to the STRUCΨk programme of the European Science Foundation for sponsoring this meeting. In few other fields is the subject of this programme—Electronic Structure Calculations for Elucidating the Complex Atomistic Behaviour of Solids and Surfaces—more relevant and during the conference it became obvious that there are two reasons for the continuing interest in this field: its inherent complexity and the obfuscating effects of impurities. The challenge that is being met by theory/modelling is to unravel systematically the complexity and to identify and deconvolute the impurity effects. EDS2000 was opened by a stimulating computer modelling session dedicated to the memory of Mike Duesbery, who would have been one of the invited speakers, had he not died tragically and prematurely. In all there was a total of sixteen lectures on theory and modelling.It was obvious that the story of dislocations in silicon was neither simple nor finished. While theories of motion largely kept to gliding partials, many papers gave evidence for the presence of vacancies and interstitials and for shuffle set dislocations under some conditions. Much excitement was generated by the prospect of advanced HRTEM techniques combined with simulations to visualize dislocations and to reveal single stacking faults (and implicitly, the presence and movement of the bounding partials and their kinks). Collective properties of dislocations (multiplication) and their interaction with impurities and radiation commanded a great deal of attention.Several sessions on III–V compounds, particularly GaN, and IV–IV alloys, showed clearly how the extra complexity deepened the intellectual challenges but offered striking improvements in devices, such as blue LEDs functioning efficiently in spite of high densities of extended defects and direct band gap heterostructures with high electron mobility.A new development at this conference was a session specific to recent advances in carbon as a semiconductor, including extended defects in diamond, graphite and fullerenes. Sponsorship from the Transdiam project under the EU Interreg II program and from the British Carbon Group is gratefully acknowledged for this session.The organizing committee for EDS conference series comprises: Anna Cavallini, Cor Claeys, Tadeusz Figielski, Amand George, Malcolm Heggie, Robert Hull, Bob Jones, Martin Kittler, Vitalii Kveder, Bernard Pichaud, Pirouz Pirouz, Sergio Pizzini, Wolfgang Schröter, Horst Strunk, Guy Vanderschaeve, Eicke Weber, Tadeusz Wosinski and Ichiro Yonenaga, with Tony Cullis and Risto Nieminen co-opted for EDS2000. We thank them for their invaluable advice when inviting speakers, and especially Bob Jones (Exeter University) on the local (national) organizing committee. The committee identified several subjects as the basis of the next EDS conference, which will most likely be held in Italy in 2002. Amongst these subjects are GaN as microwave transistors, nano-particles and their interfaces (e.g. quantum dots of silicon in silica), and wide band gap materials in general.Finally we note that participation in the conference proceedings was an entirely voluntary matter, so that the latest results could be presented without the penalty of delaying this proceedings volume. s of all talks and posters from the meeting are, however, available on the web (www.cpes.susx.ac.uk/eds2000).Dr Malcolm HeggieDr Jon Goss