Loading indirect excitons into an electrostatic trap formed in coupled GaAs quantum wells

We demonstrate how to load indirect excitons into an electrostatic trap, which is formed in a field-effect structure based on coupled GaAs quantum wells. Within the plane of a double quantum well, indirect excitons are trapped at the perimeter of a SiO2 area sandwiched between the surface of the GaAs heterostructure and a semi-transparent metallic top gate. The trapping mechanism is well explained by a combination of the quantum confined Stark effect and local field enhancement. We find that the trap can be filled with indirect excitons, as soon as the distance between the laser excitation and the trap is shorter than the effective diffusion length of the indirect excitons. (c) 2007 Elsevier B.V. All rights reserved.