Integrated Circuits and Logic Operations Based on Single-Layer MoS2

Optics has already proved its strong potentiality for the conduction of parallel logic, arithmetic and algebraic operations. In the last few decades several all-optical data processors were proposed. To implement these processors different data encoding/decoding techniques have been reported. In this context, polarization encoding technique, intensitybased encoding technique, tristate and quaternary logic operation, multivalued logic operations, symbolic substitution techniques etc. may be mentioned. Very recently, frequency encoding/decoding technique has drawn interest from the scientific community. Frequency is the fundamental character of any signal; and it remains unaltered in reflection, refraction, absorption etc. during the propagation and transmission of the signal. This is the most important advantage of frequency encoding technique over the conventional encoding techniques. In this communication the authors propose a new scheme for implementing NOT, OR and NOR logic operations. For this purpose co-propagating beams having different frequencies in C-band (1535–1560 nm) have been used for generating cascaded sum and difference frequency, exploiting the nonlinear response character of periodically poled LiNbO3 waveguide. The cross-gain modulation property of the semiconductor optical amplifier (SOA) and the wavelength conversion property of the reflecting semiconductor optical amplifiers (RSOA) are exploited here to implement the desired optical logic and arithmetic operations.

In this paper, a multifunctional layered photonic structure (LPS) with NOR logical operation and multiscale detection based on the parity-time (PT) symmetry breaking composed of magnetized yttrium iron garnet (YIG) is proposed in theory. The accurate NOR logical operation is completed by properly modulating the target resonant absorption peak (AP) by the external magnetic field and using the peak to ascertain the logical operation. Given the high-quality factor of the resulting APs, the proposed structure can be used to detect four important physical quantities, which are angle, magnetic field, the thickness of ferrite1, and refractive index (RI). YIG is a typical representative of ferrite. Due to the magneto-optical effect, the PT-symmetry is broken, resulting in a nonreciprocal phenomenon, thereby further realizing NOR logic operation and multi-physical quantity detection on the front and rear scales. Since the RI of YIG is modulated by the magnetic field, the change of the magnetic field can cause the AP generated by the resonance to shift, so that the magnetic field can be detected.

Logic circuit based on the negative differential resistance (NDR) device is demonstrated. This basic NDR device is made of four metal-oxide-semiconductor field-effect-transistor (MOS) devices that could exhibit the NDR characteristic in the current-voltage oltage curve by suitably arranging the parameters of the MOS devices. The OR and NOR logic operation will be demonstrated based on the NDR devices and circuits. The devices and circuits are implemented by the standard 0.35μm CMOS process.

In this study, we propose a novel combination of tunneling field-effect transistors (TFETs) with asymmetrically doped p+-i-n+ silicon nanowire (SiNW) channels on a bendable substrate. The combination of two n-channel SiNW-TFETs (NWTFETs) in parallel and two p-channel NWTFETs in series operates as a two-input NOR logic gate. The component NWTFETs with the n- and p-channels exhibit subthreshold swings (SSs) of 69 and 53 mV·dec−1, respectively, and the on/off current ratios are ~106. The NOR logic operation is sustainable and reproducible for up to 1,000 bending cycles with a narrow transition width of ~0.26 V. The mechanical bendability of the bendable NWTFETs shows that they are stable and have good fatigue properties. To the best of our knowledge, this is the first study on the electrical and mechanical characteristics of a bendable NOR logic gate composed of NWTFETs.

Differential phase-shift keying (DPSK) signals are promising candidate for the long-haul transmission systems. However, the development of the all-optical signal processing techniques for the DPSK signals is still in its infancy, especially the all-optical logic operations. In this work, a general scheme for reconfigurable logic gates for multi-input DPSK signals with integration possibility is proposed. Benefiting from the optical logic minterms developed by two kinds of optical devices, i.e., optical delay interferometers and semiconductor optical amplifiers (SOAs), target logic functions can be realized by combining specific minterms together. The scheme is reconfigured by changing the phase control of the delay interferometers or the input wavelengths. The latter approach was adopted in the experimental trials. Although the outputs of the scheme are on-off keying (OOK) signals, the data format is compatible with all-optical decision circuits where OOK format is preferred. Two- and three-input experiments are carried out at 20 Gbit/s with nonreturn-to-zero DPSK signals. Various logic operations are demonstrated, including full sets of two- and three-input minterms, AND, NOR, XOR, and XNOR logic operations where the AND and NOR logic are derived simultaneously and the XOR and XNOR logic are convertible. The optical SNR as well as the Q-factor of the two- and three-input results are measured and compared. It shows that the input powers to the SOAs are critical in achieving good extinction ratio and the Q-factor of logic results degrades when several minterms are combined. The recovery time of the SOAs need to be optimized as well. Finally, the scaling issues of the scheme are discussed.

The ever increasing demand for very fast and agile optical networks requires very fast execution of different optical and logical operations as well as large information handling capacities at the same time. In conventional binary logic based operations the information is represented by two distinct states only (0 and 1 state). It limits the large information handling capacity and speed of different arithmetic and optical logic operations. Tristate based logic operations can be accommodated with optics successfully in data processing, as this type of operation can enhance the speed of operation as well as increase the information handling capacity. Here in this communication the author proposes a new method to implement all-optical different logic gates with tristate logic using the frequency-encoding principle. The frequency encoding/decoding based optical communication has distinctly great advantages because the frequency is the fundamental character of an optical signal and it preserves its identity throughout the communication. The principle of the rotation of the state of polarization of a probe beam through semiconductor optical amplifier (SOA), frequency routing property of an optical add/drop multiplexer (AD) and high frequency conversion property of reflecting semiconductor optical amplifiers (RSOA) have been exploited here to implement the desired AND, OR, NAND and NOR logic operations with tristate logic.

Design of an ultrafast all-optical NOR logic gate based on Mach-Zehnder interferometer using quantum-dot SOA

A scheme of developing frequency encoded tristate logic operations exploiting nonlinear character of PPLN waveguide and RSOA

Low-voltage Zn-doped CuI thin film transistors (TFTs) gated by chitosan dielectric were fabricated at a low temperature. The Zn-doped CuI TFT exhibited a more superior on/off current ratio than CuI TFT due to the substitution or supplementation of copper vacancies by Zn ions. The Zn-doped CuI films were characterized by scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy. The Zn-doped CuI TFTs exhibited an on/off current ratio of 1.58 × 104, a subthreshold swing of 70 mV/decade, and a field effect mobility of 0.40 cm2V-1s-1, demonstrating good operational stability. Due to the electric-double-layer (EDL) effect and high specific capacitance (17.3 μF/cm2) of chitosan gate dielectric, Zn-doped CuI TFT operates at a voltage below -2 V. The threshold voltage is -0.2 V. In particular, we have prepared Zn-doped CuI TFTs with two in-plane gates and NOR logic operation is implemented on such TFTs. In addition, using the ion relaxation effect and EDL effect of chitosan film, a simple pain neuron simulation is realized on such a p-type TFTs for the first time through the bottom gate to regulate the carrier transport of the channel. This p-type device has promising applications in low-cost electronic devices, complementary electronic circuit, and biosensors.

Analytical and simulative studies on optical NOR and controlled NOR logic gates with semiconductor optical amplifier

Stateful logic can perform logic operations and simultaneously stores computational results in memory devices. Most stateful logic bases and algorithms have been studied using resistive random‐access memory devices. Herein, stateful full adders consisting of silicon p+–n–p–n+ diodes that exhibit switching and memory functions through band modulation are demonstrated. A 1‐bit full adder using ten diodes operates with ten sequential steps of material implication and NOR logic operations, and its energy consumption per operation is 50.4 pJ. Row and column logic operations in a diode crossbar structure enable an N‐bit full adder algorithm. This study demonstrates the feasibility of achieving fully functional in‐memory computations using silicon diodes.

Multibridge channel field-effect transistors (MBC-FETs) based on two-dimensional (2D) semiconductors emerge as promising candidates for achieving the ultimate scaling of transistors at advanced technology nodes. Here, the MBC-FETs based on 2D group IV-VI materials are designed by vertically stacking multiple conductive channels and gate electrodes. Concurrently, the operational mechanism underlying the device's tailored transport behaviors is comprehensively analyzed by integrating the characterizations of potential difference, local device density of states, transmission spectra, and projected device density of states. The double-gate double-channel MBC-FETs with 96.2 mV/dec subthreshold swing (SS) achieve YES, NAND, and NOR logic operations via precise electrode doping concentration control and programmable bias voltage. Moreover, the triple-gate double-channel MBC-FETs (SS = 81 mV/dec) enable the implementation of Y = A̅, NAND, and Y = B̅ logic operations. This work paves the way for developing MBC-FETs-based multifunctional logic devices for next-generation integrated circuits and continuing Moore's Law.

Magnetic logic devices have been investigated by micromagnetics simulation and experiment. The simulation shows that the magnetic logic devices composed of 4 elliptical permalloy dots perform both the NAND and NOR logic operations. The experiments indicate that the distance between adjacent dots must be shorter than 50 nm and 70 nm along the long axis and the short axis of the dots, respectively. The micro-fabricated test devices show the above logic operations.

The development of polymeric systems that can integrate individual basic logic gates into combinational circuits has been extremely interesting as smart materials. A novel thermometer fluorescent sensor poly(NIPMAM-co-MDCPDP) consisting of N-isopropylmethacrylamide (NIPMAM) as a thermoresponsive unit and dicyanomethylene-4H-pyran derivative as a dipolar-sensitive fluorophore unit was designed. Poly(NIPMAM-co-MDCPDP) performs fluorescence quenching merely by coordination with Cu2+ ions or increasing temperature in neutral or acid aqueous solution. The ON−OFF fluorescence response of poly(NIPMAM-co-MDCPDP) is driven by a temperature-induced phase transition from coil to globule and the capture of Cu2+ ions, resulting in a decrease of the ICT efficiency in neutral solution. The combinational serial NOR logic operation as well as two INHIBIT logic gates was constructed with three inputs: various pH, temperature change, and Cu2+ ions. The proposed combinational logic circuits play a key role in mimicking compr...

Optics has already proved its strong potentiality for conducting parallel logic, arithmetic and algebraic operations. Since last few decades so many all-optical data processors were proposed. To implement these processors different encoding / decoding techniques, such as polarization encoding, intensity encoding, phase encoding technique have been reported. Very recently ‘frequency encoding’ technique have drawn a special interest to the scientific community. The frequency is the fundamental character of a signal and it preserves its identity irrespective of reflection, refraction, transmission, absorption throughout the communication. Therefore, if two specific frequencies are encoded as 1 state and 0 states respectively, then one can ensure about the state of information throughout the communications. In this paper the authors propose a method of conducting inversion OR, NOR and NAND logic operations exploiting the wavelength conversion, which is achieved by exploiting the cross gain modulation (XGM) property of reflecting semiconductor optical amplifier (RSOA), as well as the property of change of nonlinear rotation of the state of polarization of probe beam by cross phase modulation (XPM). Both the wavelength conversion properties are controlled by the intensity of the pump beam. The major advantage of SOA-switching over any other conventional switching is that SOA-switching require low power with good on off contrast ratio. Again as the NAND and NOR are the universal logic gates, so any other logic operation can be implemented using this concept.