Behavior of Al-Al2O3-Al single-electron transistors from 85 mK to 5 K

Using e-beam lithography and conventional double-angle evaporation, we have fabricated Al-Al2O3-Al single-electron transistors and studied their behavior from 85 mK to about 5 K. The total island capacitance C-Sigma of the devices ranges from 120 to 200 aF, with typical estimated junction overlaps of about 30 nmX30 nm. At 4.2 K, our devices display well-behaved periodic I-V-g characteristics with the maximum charge-transfer function partial derivative I/partial derivative Q(0) ranging from 4 to 130 pA/e. The electrical characteristics of these devices agree well with the predictions of the Orthodox Theory, with current modulation being observed up to a temperature T similar or equal to e(2)/(2C(Sigma)k(B)). Below 1 K small deviations occur, which are partly due to island self-heating effects. (C) 1998 American Institute of Physics.