the full adders (fas) constitute the essential elements of digital systems, in a sense that they affect the circuit parameters of such systems. with respect to the mosfet restrictions, its replacement by new devices and technologies is inevitable. qca is one of the accomplishments in nanotechnology nominated as the candidate for mosfet replacement. in this article 4 new layouts are presented fo...

Quantum dot Cellular Automata (QCA) is a novel and potentially attractive technology for implementing computing architectures at the nano-scale. The basic Boolean primitive in QCA is the majority gate. In this paper we present a novel design for QCA cells and another possible and unconventional scheme for majority gates. By applying these items, the hardware requirements for a QCA design can be...

Quantum-dot cellular automata (QCA) are a transistorless computation approach which encodes binary information via configuration of charges among quantum dots. The fundamental QCA logic primitives are majority and inverter gates which can be utilized to design various QCA circuits. This study presents a novel approach to designing efficient QCA-based circuits based on Boolean expressions achiev...

Quantum-dot cellular automata ~QCA! may provide a novel way to bypass the transistor paradigm to form ultrasmall computing elements. In the QCA paradigm information is represented in the charge configuration of a QCA cell, which maps naturally to a binary model. Molecular QCA implementations are being explored where the quantum dots in the cell take the form of redox centers in a molecule. Cloc...

   One of the several promising new technologies for computing at nano-scale is quantum-dot cellular automata (QCA). In this paper, new designs for different QCA sequential circuits are presented. Using an efficient QCA D flip-flop (DFF) architecture, a 5-bit counter, a novel single edge generator (SEG) and a divide-by-2 counter are implemented. Also, some types of oscillators, a new edge-t...

While still relatively “new”, the quantum-dot cellular automata (QCA) appears to be able to provide many of the properties and functionalities that have made CMOS successful over the past several decades. Early experiments have demonstrated and realized most, if not all, of the “fundamentals” needed for a computational circuit – devices, logic gates, wires, etc. This study introduces the beginn...

Quantum-dot cellular automata (QCA) technology is considered to be a possible alternative for circuit implementation in terms of energy efficiency, integration density and switching frequency. Multiplexer (MUX) can suitable candidate designing QCA circuits. In this paper, two different structures energy-efficient 2×1 MUX designs are proposed. These MUXes outperform the best existing design powe...

The new architecture for quantum cellular automata is offered. A QCA cell includes two layers nc-Si, divided by a dielectric. Among themselves cells are connected by the bridge from a conductive material. The comparison is made between this and QCA, offered earlier by C. Lent's group. Keywords—quantum cellular automata (QCA), nc-Si, Si/SiO2 superlattices, parallel computing

A Quantum Cellular Automaton (QCA) is a nanotechnology which is an attractive alternative for transistor based technologies in the near future. A new seven input majority gate in quantum dot cellular automata is proposed in this paper. The basic elements in QCA are majority and inverter gates, therefore using a majority gate with more inputs in QCA circuit will cause reduction in cell count, la...

We establish a method for exploring the dynamics of molecular quantum-dot cellular automata QCA devices by hierarchically combining the techniques of quantum chemistry with the nonequilibrium time-dependent coherence vector formalism. Single QCA molecules are characterized using ab initio quantum chemistry methods. We show how to construct a simple model Hamiltonian for each QCA cell based on p...