Konrad Walus

QCADesigner: a rapid design and Simulation tool for quantum-dot cellular automata

This paper describes a project to create a novel design and simulation tool for quantum-dot cellular automata (QCA), namely QCADesigner. QCA logic and circuit designers require a rapid and accurate simulation and design layout tool to determine the functionality of QCA circuits. QCADesigner gives the designer the ability to quickly layout a QCA design by providing an extensive set of CAD tools. As well, several simulation engines facilitate rapid and accurate simulation. This tool has already been used to design full-adders, barrel shifters, random-access memories, etc. These verified layouts provide motivation to continue efforts toward a final implementation of QCA circuits.

A method of majority logic reduction for quantum cellular automata

The basic Boolean primitive in quantum cellular automata (QCA) is the majority gate. In this paper, a method for reducing the number of majority gates required for computing three-variable Boolean functions is developed to facilitate the conversion of sum-of-products expression into QCA majority logic. Thirteen standard functions are introduced to represent all three-variable Boolean functions and the simplified majority expressions corresponding to these standard functions are presented. We describe a novel method for using these standard functions to convert the sum-of-products expression to majority logic. By applying this method, the hardware requirements for a QCA design can be reduced. As an example, a 1-bit QCA adder is constructed with only three majority gates and two inverters. The adder is designed and simulated using QCADesigner, a design and simulation tool for QCA. We will show that the proposed method is very efficient and fast in deriving the simplified majority expressions in QCA design.

Quantum-dot cellular automata adders

In this paper, a novel quantum-dot cellular automata (QCA) adder design is presented that reduces the number of QCA cells compared to previously reported designs. The proposed one-bit QCA adder structure is based on a new algorithm that requires only three majority gates and two inverters for the QCA addition. By connecting n one-bit QCA adders, we can obtain an n-bit carry look-ahead adder with the reduced hardware while retaining the simple clocking scheme and parallel structure of the original carry look-ahead approach. The proposed adder is designed and simulated using the QCA Designer tool for the four-bit adder case. The proposed design requires only about 70% of the hardware compared to previous designs with the same speed and clocking performance.

Design Tools for an Emerging SoC Technology: Quantum-Dot Cellular Automata

The future of system-on-chip (SoC) technologies, based on the scaling of current FET-based integrated circuitry, is being predicted to reach fabrication limits by the year 2015. Economic limits may be reached before that time. Continued scaling of electronic devices to molecular scales will undoubtedly require a paradigm shift from the FET-based switch to an alternative mechanism of information representation and processing. This paradigm shift will also have to encompass the tools and design culture that have made the current SoC technology possible-the ability to design monolithic integrated circuits with many hundreds of millions of transistors. In this paper, we examine the initial development of a tool to automate the design of one of the promising emerging nanoelectronic technologies, quantum-dot cellular automata, which has been proposed as a computing paradigm based on single electron effects within quantum dots and molecules.

Paper as a platform for sensing applications and other devices: a review.

Paper is a ubiquitous material that has various applications in day to day life. A sheet of paper is produced by pressing moist wood cellulose fibers together. Paper offers unique properties: paper allows passive liquid transport, it is compatible with many chemical and biochemical moieties, it exhibits piezoelectricity, and it is biodegradable. Hence, paper is an attractive low-cost functional material for sensing devices. In recent years, researchers in the field of science and engineering have witnessed an exponential growth in the number of research contributions that focus on the development of cost-effective and scalable fabrication methods and new applications of paper-based devices. In this review article, we highlight recent advances in the development of paper-based sensing devices in the areas of electronics, energy storage, strain sensing, microfluidic devices, and biosensing, including piezoelectric paper. Additionally, this review includes current limitations of paper-based sensing devices and points out issues that have limited the commercialization of some of the paper-based sensing devices.

Performance comparison of quantum-dot cellular automata adders

QCA adders are fundamental building blocks of complex QCA computational units. In our analysis, we show that QCA ripple-carry adder and bit-serial adder designs actually outperform carry-look-ahead and carry-select adder designs. The QCA ripple-carry and bit-serial adders require fewer clocking zones, which have been found to be the main contributing factor toward overall circuit latency.

Circuit design based on majority gates for applications with quantum-dot cellular automata

Majority gate-based logic is not normally explored with standard CMOS technologies, primarily because of the hardware inefficiencies in creating majority gates. As a result, not much effort has been made towards the optimization of circuits based on majority gates. We are exploring one particular emerging technology, quantum-dot cellular automata (QCA), in which the majority gate is the fundamental logic primitive. We report a simple and intuitive method for reduction of three-variable Boolean functions into a simplified majority representation. The method is based on Karnaugh maps (K-maps), used for the simplification of Boolean functions.

High Level Exploration of Quantum-Dot Cellular Automata (QCA)

In this work, we present a high level evaluation of an emerging nanotechnology to determine a set of technology requirements. The technology under question is Quantum-Dot Cellular Automata (QCA). As a vehicle, we present two different QCA circuits and evaluate the technology requirements based on the specifications of these circuits. These circuits are a simple 4-bit arithmetic logic unit (ALU) and a 4/spl times/4 memory which are building blocks to more complex systems such as a computer central processing unit (CPU).

Simple 4-bit processor based on quantum-dot cellular automata (QCA)

We describe the design and layout of a simple 4-bit processor based on quantum dot cellular automata (QCA) using the QCADesigner design tool. The processor design is based on an accumulator architecture which reduces the required hardware complexity and allows for reasonable simulation times. Our aim is to provide evidence that QCA has potential applications in future computers provided that the underlying technology is made feasible.

Substrate‐Free Fabrication of Self‐Supporting ZnO Nanowire Arrays

Thin films composed of self-supporting ZnO nanowire arrays are fabricated via a hydrothermal approach without the presence of any substrates. The films can be transferred and bonded to an arbitrary substrate for device applications. As a demonstration, a piezoelectric converter is made which is able to generate electric charge under compressive forces.