Theoretical Investigation of New Quantum-Cross-Structure Device as a Candidate beyond CMOS

Abstract

We propose a new quantum cross structure (QCS) device as a candidate beyond CMOS. The QCS consists of two metal nano-ribbons having edge-to-edge configuration like crossed fins.The QCS has potential application in both switching devices and high-density memories by sandwiching a few molecules and atoms. The QCS can also have electrodes with different dimensional electron systems because we can change the widths, the lengths, and the heights of two metal nano-ribbons, respectively. Changing the dimensions of electron systems in both electrodes, we have calculated the current-voltage characteristics depending on the coupling constants between a molecule and the electrode. We find that the conductance peak is much sharper in case of weak coupling regardless of dimensions of electron systems in electrodes, compared to strong coupling case. We also find that the conductance peak of QCS having electrodes with two-dimensional electron systems (2DES) is much sharper than that of QCS having electrodes with three-dimensional electron systems (3DES) in case of strong coupling because of quantum size effect of 2DES. These results imply that the QCS with the very sharp conductance peak can serve as the devices to switch on and off by very small voltage change.

The fabrication of Ni quantum cross devices with a 17 nm junction and their current–voltage characteristics

“…where e is the elementary charge, E F is the Fermi energy of Ni, and ) ( f is the Fermi-Dirac distribution function [11]. we estimate the switching on/off ratio, the I 1 /I 0 ratio is found to be an excess of 100000:1.…”

“…Utilizing this DNB structure, we can expect to realize high-density memory devices, the cross point of which can be scaled down to ultimate feature sizes of a few nanometers thanks to the film thickness determined by the metal-deposition rate, ranging from 0.01 to 1 nm/s. One element of the DNB structure is called a quantum cross (QC) device that consists of two metal nanoribbons having the edge-to-edge configuration [9][10][11]. When molecular-based self-assembled monolayers (SAMs) [12][13][14], such as rotaxanes, catenanes and pseudorotaxanes, are sandwiched between the two thin metal ribbons, QC devices can serve as novel non-volatile memory devices and switching devices.…”

Fabrication of Nickel/Organic-Molecule/Nickel Nanoscale Junctions Utilizing Thin-Film Edges and Their Structural and Electrical Properties

“…1. [9][10][11][12][13] In this QC device, the area of the crossed section is determined by film thickness, that is, 1-20 nm thick films could produce 1 Â 1-20 Â 20 nm 2 nanoscale junctions. This method offers a way to overcome the feature size limit of conventional optical lithography.…”

Large Thermoelectric Voltage in Point Contacts of Ni Ferromagnetic Metals

“…In this paper, we have theoretically investigated thermoelectric effects in PCs of Ni ferromagnetic metals using spin quantum cross structure (SQCS) devices, and we have verified the thermoelectric effects in PCs of Ni ferromagnetic metals experimentally. The SQCS device consists of two ferromagnetic metal thin films with their edges crossing, and sandwiches a few molecules and atoms [3][4][5][6]. The junction area made of two edges can be scaled down to nanometer size due to the good resolution in making films by the metal-deposition rate, ranging from 0.01 nm/s to 1 nm/s.…”