We report the fabrication and electrical characterization of depletion-mode quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use fixed charge in a SiO2/Al2O3 dielectric stack to induce a 2DHG at the Si/SiO2 interface. Fabrication of the gate structures is accomplished with a single layer metallization process. Transport spectroscopy reveals regular Coulomb oscillations with charging energies of 10-15 meV and 3-5 meV for the few- and many-hole regimes, respectively. This depletion-mode design avoids complex multilayer architectures requiring precision alignment, and allows to adopt directly best practices already developed for depletion dots in other material systems. We also demonstrate a method to deactivate fixed charge in the SiO2/Al2O3 dielectric stack using deep ultraviolet light, which may become an important procedure to avoid unwanted 2DHG build-up in Si MOS quantum bits.
@article{arxiv.1709.07361,
title = {Depletion-mode Quantum Dots in Intrinsic Silicon},
author = {Sergey V. Amitonov and Paul C. Spruijtenburg and Max W. S. Vervoort and Wilfred G. van der Wiel and Floris A. Zwanenburg},
journal= {arXiv preprint arXiv:1709.07361},
year = {2018}
}
Comments
Accepted to Applied Physics Letters. 5 pages, 3 figures