Architecture for an external input into a molecular QCA circuit

Walus, Konrad; Karim, Faizal; Ivanov, A.

doi:10.1007/s10825-009-0268-0

Cited by 17 publications

(5 citation statements)

References 19 publications

(25 reference statements)

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“…DNA tiles have been proposed for self-assembled molecular QCA circuit layout [32]. A previous proposal for molecular QCA write-in exists, but it requires the use of fixed-state QCA molecules as well as mastery over the layout of individual molecules [7]. Another previous proposal for inputs to molecular QCA circuits assumed an electric field with single-molecule specificity [8].…”

Section: Overview Of Qcamentioning

confidence: 99%

“…This solution consists of lithographically-formed input electrodes and molecular QCA circuits responsive to an applied electrostatic field. An earlier approach to molecular QCA inputs [7] requires the use of complementary sets of fixed QCA cells, which likely would be molecules of a species different from that which comprises the rest of the QCA circuitry. On the other hand, the approach presented here does not require special fixed molecules.…”

Section: Introductionmentioning

confidence: 99%

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Electric-Field Inputs for Molecular Quantum-Dot Cellular Automata Circuits

Blair

2019

IEEE Trans. Nanotechnology

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Quantum-dot cellular automata (QCA) is a lowpower, non-von-Neumann, general-purpose paradigm for classical computing using transistor-free logic. An elementary QCA device called a "cell" is made from a system of coupled quantum dots with a few mobile charges. The cell's charge configuration encodes a bit, and quantum charge tunneling within a cell enables device switching. Arrays of cells networked locally via the electrostatic field form QCA circuits, which mix logic, memory and interconnect. A molecular QCA implementation promises ultra-high device densities, high switching speeds, and roomtemperature operation. We propose a novel approach to the technical challenge of transducing bits from larger conventional devices to nanoscale QCA molecules. This signal transduction begins with lithographically-formed electrodes placed on the device plane. A voltage applied across these electrodes establishes an in-plane electric field, which selects a bit packet on a large QCA input circuit. A typical QCA binary wire may be used to transmit a smaller bit packet of a size more suitable for processing from this input to other QCA circuitry. In contrast to previous concepts for bit inputs to molecular QCA, this approach requires neither special QCA cells with fixed states nor nanoelectrodes which establish fields with single-electron specificity. A brief overview of the QCA paradigm is given. Proof-of-principle simulation results are shown, demonstrating the input concept in circuits made from two-dot QCA cells. Importantly, this concept for bit inputs to molecular QCA may enable solutions to or provide insights into other challenges to the realization of molecular QCA, such as the demonstration of molecular device switching, the read-out of molecular QCA states, and the layout of molecular QCA circuits.

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Section: Overview Of Qcamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electric-Field Inputs for Molecular Quantum-Dot Cellular Automata Circuits

Blair

2019

IEEE Trans. Nanotechnology

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“…The cell's size is 18 × 18 nanometers, and dots are put in the corners. 13 Tunneling between two neighboring quantum dots allows free electrons to flow. The logical "0" or "1" is determined by how electrons are placed inside dots.…”

Section: Principles Faults and Fault-tolerant Circuitsmentioning

confidence: 99%

A New Nano-Design of a Fault-Tolerant Coplanar RAM with Set/Reset Ability Based on Quantum-Dots

Wei¹,

Guo²

2022

ECS J. Solid State Sci. Technol.

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Quantum Dot Cellular Automata (QCA) is a recent technology that has piqued researchers’ interest because of its small size and low energy consumption. With the help of quantum dots, the QCA technology delivers a new computational foundation for constructing digital circuits. Medical imaging and quantum computing are just a few applications for quantum dots. Quantum dots are nanocrystals that transmit data at the nano-scale. Since the memory is an important digital circuit, this work proposes a fault-tolerant loop-based coplanar Random Access Memory (RAM) with set/reset capability that uses the QCA rules. The memory cell’s operation is verified both physically and through simulations with the QCADesigner program. The quantum cost of the proposed memory cell shows that it has a negligible quantum cost. The proposed QCA-based memory circuit performs well in simulations, with 96 QCA cells and the output signal generated after 0.75 clock phases. The gates and wire in this design have around 85 percent better fault-tolerant capability than the best-presented memory systems. Furthermore, this circuit can tolerate most cell omission, displacement, misalignment, and deposition faults. This structure can be used to create high-performance higher-order fault-tolerant memory structures.

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“…One challenge in molecular QCA is the write-in of classical bits on nano-scale molecules. While some techniques have been proposed for bit-write-in to molecular QCA circuits [6], [7], we have proposed a technique that requires neither special fixed-state QCA molecules nor electrodes with singlemolecule specificity [8]. Quantum models of asynchronous QCA circuits were used to demonstrate that charged electrodes much larger than the molecules could be used to apply an input electric field to the molecular circuitry and write bits onto several molecules.…”

Section: Introductionmentioning

confidence: 99%

Robust Electric-field Input Circuits for Clocked Molecular Quantum-dot Cellular Automata

Cong,

Blair

2021

Preprint

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Quantum-dot cellular automata (QCA) is a paradigm for low-power, general-purpose, classical computing designed to overcome the challenges facing CMOS in the extreme limits of scaling. A molecular implementation of QCA offers nanometer-scale devices with device densities and operating speeds which may surpass CMOS device densities and speeds by several orders of magnitude, all at room temperature. Here, a proposal for electric field bit write-in to molecular QCA circuits is extended to synchronous QCA circuits clocked using an applied electric field, E. Input electrodes, which may be much larger than the cells themselves, immerse an input circuit in an input field Ey ŷ, in addition to the applied clocking field Ez ẑ. The input field selects the input bit on a field-sensitive portion of the circuit. Another portion of the circuit with reduced Eysensitivity functions as a shift register, transmitting the input bit to downstream QCA logic for processing. It is shown that a simple rotation of the molecules comprising the shift register makes them immune to unwanted effects from the input field or fringing fields in the direction of the input field. Furthermore, the circuits also tolerate a significant unwanted field component Ex x in the third direction, which is neither the clocking nor input direction. The write-in of classical bits to molecular QCA circuits is a road-block that must be cleared in order to realize energy-efficient molecular computation using QCA. The results presented here show that interconnecting shift registers may be designed to function in the presence of significant unwanted fringing fields from large input electrodes. Furthermore, the techniques devloped here may also enable molecular QCA logic to tolerate these same unwanted fringing fields.

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Architecture for an external input into a molecular QCA circuit

Cited by 17 publications

References 19 publications

Electric-Field Inputs for Molecular Quantum-Dot Cellular Automata Circuits

Electric-Field Inputs for Molecular Quantum-Dot Cellular Automata Circuits

A New Nano-Design of a Fault-Tolerant Coplanar RAM with Set/Reset Ability Based on Quantum-Dots

Robust Electric-field Input Circuits for Clocked Molecular Quantum-dot Cellular Automata

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