Work Area: Nanoelectronics
Keywords nanoelectronics, transport properties, growth, processing, characterisation of vertical tunnelling components
Start Date: 1 October 92 / Duration: 36 months / Status: running
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Abstract This project studies the physics and potential device applications of resonant tunnelling and related structures. Demonstrator components are resonant tunnelling light-emitting diodes for the near-infrared, single- and double-barrier varactors, and double-barrier interband tunnelling structures. Analysis tools are microscopic steady-state, picosecond- and femtosecond-resolved spectroscopies with and without the application of magnetic fields or hydrostatic pressure.
The main goal of PARTNERS is the creation of new classes of devices based on the most recent findings in tunnelling transport. Three basic activities will play a crucial role in the realisation of the aims:
The members of the consortium have all been responsible for international pioneering work in this field. Building upon the most recent developments in the various laboratories, the partners will formulate a series of devices to form the framework of the work. In many cases, prototypes of the proposed devices have already been constructed and exhibit promising characteristics that would be relevant for future industrial applications.
The essential theme of the research will be to gain understanding of the basic physics underlying the operation of the devices. Each device will be pushed to its performance limits using all the techniques and expertise available. Exploitable devices will be identified and redesigned to maximise their industrial applicability by careful selection of growth and fabrication parameters. Specific, desirable properties will be emphasised with this approach. Feedback between the three areas of theory, analysis and fabrication should produce the ultimate goal: a series of prototype devices available to the European semiconductor industry for further development.
By modifying the basic double-barrier resonant tunnelling light-emitting diode (RTLED) structure, drastic improvements in optical characteristics have been obtained by the groups working on the RTLED. The main point was the formation of a triple-barrier structure with either strong or weak coupling between the quantum wells. It has resulted in giant optical bistable behaviour or intense spatially indirect emission that strongly red-shifts with bias. Higher-energy tansitions (near-visible wavelength range) have been obtained both in double-barrier and in superlattice RTLEDs. This non-thermal occupation of higher subbands indicates the possibility of intersubband transitions leading to infrared emission.
Collaboration between three partners has resulted in successfully processed InAs/AlSb interband resonant tunnelling diodes. Finally, our theoreticists have been able to accurately model intrinsic bistability and its breakdown in double-barrier resonant tunnelling structures. Modelling of triple-barrier structures has started.
Although the research carried out by the different institutions and the value offered by cooperation ensures a long-term industrial potential, the project is developing basic technology that industry will need in the medium term. Real applications are foreseen in consumer electronics, telecommunications and space. Major interest in the consortium's work has already been expressed by various European system houses.
A number of publications originating from this work (several still in press) are available from the coordinator. Also the consortium has presented its results on international conferences. Meetings have been held in Grenoble (CNRS/SNCI-INSA) in October, 1992 and in Göteborg (Chalmers University of Technology) in April 1993.
IMEC vzw - B
B - 3001 LEUVEN
Max-Planck Institut für Festkörperforschung - D
CNRS-INSA - F
Chalmers University of Technology - S
Linkoeping University - S
University of Nottingham - UK
Prof. G. Borghs
tel +32/16 281 287
fax +32/16 281501
PARTNERS - 7193, August 1994
please address enquiries to the ESPRIT Information Desk
html version of synopsis by Nick Cook