Time-resolved electron dynamics in coupled quantum dots is directly observed by a pulsed-gate technique. While individual gate voltages are modulated with periodic pulse trains, average charge occupations are measured with a nearby quantum point contact as detector. A key component of our setup is a sample holder optimized for broadband radio frequency applications. Our setup can detect displacements of single electrons on time scales well below a nanosecond. Tunneling rates through individual barriers and relaxation times are obtained by using a rate equation model. We demonstrate the full characterization of a tunable double quantum dot using this technique, which could also be used for coherent charge qubit control.
@article{arxiv.1006.5554,
title = {Radio frequency pulsed-gate charge spectroscopy on coupled quantum dots},
author = {D. Harbusch and S. Manus and H. P. Tranitz and W. Wegscheider and S. Ludwig},
journal= {arXiv preprint arXiv:1006.5554},
year = {2010}
}