Simultaneous operation of two adjacent double dots in silicon

We have studied the electrical transport through two adjacent double dot structures realized in Si-on-insulator material. The small dimensions of dots and the distance between the centers of the dots, here 100 nm, allow for dc measurements at 4.2 K. We demonstrate that although the structures are entirely doped, we are able to operate both double dot structures simultaneously in the double dot regime. Clear Coulomb blockade characteristics with a Coulomb blockade region of 20 mV are observed in both structures. Using gates, the number of electrons on each individual dot can be manipulated simultaneously. From the measured charging diagrams the capacitances between the gates and the dots are determined. (C) 2001 American Institute of Physics.