Observation of Charge Transport by Negatively Charged Excitons
Daniele Sanvitto,12
Fabio Pulizzi,3
Andrew J. Shields,1*
Peter C. M. Christianen,3
Stuart N. Holmes,1
Michelle Y. Simmons,2
David A. Ritchie,2
Jan C. Maan,3
Michael Pepper12
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 6.5 × 104
cm2 V
1 s1. The results
demonstrate that X- exists as a free particle in the
best-quality samples and suggest that light emission from
opto-electronic devices can be manipulated through exciton drift under
applied electric fields.
1 Toshiba Research Europe Limited, Cambridge
Research Laboratory, 260 Cambridge Science Park, Milton Road,
Cambridge, CB4 0WE, UK.
2 Cavendish
Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3
0HE, UK.
3 High Field Magnet Laboratory,
University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, Netherlands.
*
To whom correspondence should be addressed. E-mail:
andrew.shields{at}crl.toshiba.co.uk
Present address: School of Physics, University of New South
Wales, Sydney 2052, Australia.
