Exciton ionization in a quantum well studied by surface acoustic waves
Abstract
Photogenerated excitons in a semiconductor quantum well are ionized by the strong lateral piezoelectric field of an intense surface acoustic wave. The ionization process is directly observed by the absorption of a second sound wave probing the areal conductivity of the photogenerated charges. Above a certain threshold field strength of the pumping surface wave the neutral excitons are dissociated into electron-hole pairs, which is indicated by a sudden onset of absorption of the probe wave. By selectively tuning the energy of the exciting laser, the dissociation of both quasi two-dimensional excitons in the quantum well as well as three-dimensional excitons in the barrier material can be observed.
- Publication:
-
Physical Review B
- Pub Date:
- March 1998
- DOI:
- 10.1103/PhysRevB.57.R6850
- Bibcode:
- 1998PhRvB..57.6850R
- Keywords:
-
- 77.65.Dq;
- 78.20.Hp;
- 78.55.Cr;
- Acoustoelectric effects and surface acoustic waves in piezoelectrics;
- Piezo- elasto- and acoustooptical effects;
- photoacoustic effects;
- III-V semiconductors