Submitted on November 2, 2000
Accepted on January 21, 2001
Observation of Charge Transport by Negatively Charged Excitons
Daniele Sanvitto 1,
Fabio Pulizzi 2,
Andrew J. Shields 3*,
Peter C. M. Christianen 2,
Stuart N. Holmes 3,
Michelle Y. Simmons 4,
David A. Ritchie 5,
Jan C. Maan 2,
Michael Pepper 1
1 Toshiba Research Europe Limited, Cambridge Research Laboratory, 260 Cambridge Science Park, Milton Road, Cambridge, CB4 0WE, UK; Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK.
2 High Field Magnet Laboratory, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands.
3 Toshiba Research Europe Limited, Cambridge Research Laboratory, 260 Cambridge Science Park, Milton Road, Cambridge, CB4 0WE, UK.
4 School of Physics, University of New South Wales, Sydney 2052, Australia; Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK.
5 Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK.
* To whom correspondence should be addressed. E-mail: andrew.shields{at}crl.toshiba.co.uk.
We report transport of electron-hole complexes in semiconductor quantum wells under applied electric fields. Negatively charged excitons (X-), created by laser excitation of a high electron mobility transistor, are observed to drift upon applying a voltage between the source and drain. In contrast, neutral excitons do not drift under similar conditions. The X- mobility is found to be as high as 6.5x104cm2V-1s -1. The results demonstrate that X- exists as a free particle in the best quality samples and suggests that light emission from opto-electronic devices can be manipulated through exciton drift under applied electric fields.
