Showing papers by "Craig S. Lent published in 2004"
18 Oct 2004
TL;DR: An introduction to of quantum-dot cellular automata (QCA) is presented, which offers the possibility of circuitry that dissipates many orders of magnitude less power than CMOS, is scalable to molecular dimensions, and provides the power gain necessary to restore signal levels.
Abstract: An introduction to of quantum-dot cellular automata (QCA) is presented. QCA is a transistorless nanoelectronic computation paradigm that addresses the issues of device and power density which are becoming increasingly important in the electronics industry. Scaling of CMOS is expected to come to an end in the next 10-15 years, with perhaps the most important limiting problem being the power density and the resulting heat generated. QCA offers the possibility of circuitry that dissipates many orders of magnitude less power than CMOS, is scalable to molecular dimensions, and provides the power gain necessary to restore signal levels. QCA cells are scalable to molecular dimensions and initial measurements have demonstrated single-electron switching within a molecule.
49 citations
16 Aug 2004
TL;DR: The feasibility of using single walled carbon nanotubes (SWNTs) to implement the clocked fields, effectively removing the clocking wire barrier to greater circuit densities is explored.
Abstract: Quantum-dot cellular automata (QCA) is a computing model that has shown great promise for efficient molecular computing. The QCA clock signal consists of an electric field being raised and lowered. The wires needed to generate the clocking field have been thought to be the limiting factor in the density of QCA circuits. This paper explores the feasibility of using single walled carbon nanotubes (SWNTs) to implement the clocking fields, effectively removing the clocking wire barrier to greater circuit densities.
31 citations
21 Jun 2004
TL;DR: In this article, the scaling limits of energy dissipation in a specific and concrete physical model -that of clocked quantum-dot cellular automata (QCA) are examined. But the authors do not consider the effect of the logical structure of the calculation on the heat generated by a circuit.
Abstract: We examine the scaling limits of energy dissipation in a specific and concrete physical model - that of clocked quantum-dot cellular automata (QCA). Prototype QCA devices exist and have demonstrated true power gain, an essential feature for any general-purpose computational technology. Though present devices operate at cryogenic temperatures, much work has been done on molecular implementations which can operate at room temperature and are notably smaller than 1.5 nm. QCA represents a radical departure from CMOS, but is still a charge-based binary approach. We solve the equations of motion for the system in the presence of a thermal environment with no a priori assumptions about energy flow. We show directly the effect of the logical structure of the calculation on the heat generated by a circuit. These calculations point to the real nature of the thermodynamic limitations of scaling binary logic devices and suggest strategies for achieving the ultimate limits of device scaling.
2 citations