Papers by Keyword: Coulomb Blockade

Abstract: We propose a novel single-electron refrigerator (SER) which can be fabricated in silicon-on-insulator wafers. The SER has a structure of single-electron box combined with single-electron pump (SEP). An equivalent circuit of the SEP-refrigerator is represented and its stability diagram (Coulomb diamond) is theoretically calculated. It is found that the stability diagram has a honeycomb structure. Moreover, the operation of the single-electron transfer and single-electron storage is numerically demonstrated using a Monte Carlo simulation based on the orthodox theory of the Coulomb blockade phenomenon.

Abstract: Small single-electron devices (SEDs) consisting of many Si nanodots are fabricated on a silicon-on-insulator (SOI) wafer by means of pattern-dependent oxidation (PADOX) method. We investigated SEDs from two kinds of viewpoint. One is how to fabricate the nanodots, especially coupled nanodots, which are important to achieve quantum computers and single-electron transfer devices. The other is demonstration of new applications that tolerate the size fluctuation. In order to achieve multi-coupled nanodots, we developed an easy method by applying PADOX to a specially designed Si nanowire which has small constrictions at the ends of the wire. We confirmed the double-dot formation and position of the Si nanodots in the wire by analyzing the measured electrical characteristics. To achieve high functionality together with low-power consumption and tolerance to size fluctuation, we developed nanodot array device which has many input gates and outputs terminals. The fabricated three-input and two-output nanodot device actually provide high functionality such as a half adder and a full adder.

Abstract: In this paper, we present a study on the contribution of silicon nanocrystals to the electrical transport characteristics of large (100 m x 100 m) and small (100 nm x 100 nm) metaloxide- semiconductor (MOS) capacitors at room temperature. A layer of silicon nanocrystals is synthesized within the oxide of these capacitors by ultra-low energy ion implantation and annealing. Several features including negative differential resistance (NDR), sharp current peaks and random telegraph signal (RTS) are demonstrated in the current-voltage and current-time characteristics of these capacitors. These features have been associated to charge storage in silicon nanocrystals and to the resulting Coulomb interaction between the stored charges and the tunneling current. Clear transition from a continuous response of large capacitors to a discrete response of small capacitors reveals the quantized nature of the charge storage phenomenon in these nanocrystalline dots. The effect of the nanocrystal density from nearly continuous layer to isolated nanodots is also presented.