Observation of Charge Transport by Negatively Charged Excitons

Abstract

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 × 10 ⁴ cm ² V ⁻¹ s ⁻¹ . 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.