Temperature and Size Effect on the Electrical Properties of Monolayer Graphene based Interconnects for Next Generation MQCA based Nanoelectronics

Graphene interconnects have been projected to out-perform Copper interconnects in the next generation Magnetic Quantum-dot Cellular Automata (MQCA) based nano-electronic applications. In this paper a simple two-step lithography process for patterning CVD monolayer graphene on SiO2/Si substrate has been used that resulted in the current density of one order higher magnitude as compared to the state-of-the-art graphene-based interconnects. Electrical performances of the fabricated graphene interconnects were evaluated, and the impact of temperature and size on the current density and reliability was investigated. The maximum current density of 1.18 x 108 A/cm2 was observed for 0.3 μm graphene interconnect on SiO2/Si substrate, which is about two orders and one order higher than that of conventionally used copper interconnects and CVD grown graphene respectively, thus demonstrating huge potential in outperforming copper wires for on-chip clocking. The drop in current at 473 K as compared to room temperature was found to be nearly 30%, indicating a positive temperature coefficient of resistivity (TCR). TCR for all cases were studied and it was found that with decrease in width, the sensitivity of temperature also reduces. The effect of resistivity on the breakdown current density was analysed on the experimental data using Matlab and found to follow the power-law equations. The breakdown current density was found to have a reciprocal relationship to graphene interconnect resistivity suggesting Joule heating as the likely mechanism of breakdown

Tunable intrinsic magnetic phase transition in pristine single-layer graphene nanoribbons

In this paper, we report on the interesting phenomenon of magnetic phase transitions (MPTs) observed under the combined influence of an electric field (E) and temperature (T) leading to a thermo-electromagnetic effect on the pristine single-layer zigzag graphene nanoribbon (szGNR). Density functional theory-based first principles calculations have been deployed for this study on the intrinsic magnetic properties of graphene. Interestingly, by tuning electric field (E) and temperature (T), three distinct magnetic phase behaviors, para-, ferro- and antiferromagnetic are exhibited in pristine szGNR. We have investigated the unrivaled positional parameters of these MPTs. MPT occurring in the system also follows a positional trend and the change in these positional parameters with regard to the size of the szGNR along with the varied E and T is studied. We propose a bow-tie schematic to induce the intrinsic magnetism in graphene and present the envisaged model of the processor application with the reported intrinsic MPT in szGNR. This fundamental insight into the intrinsic MPTs in graphene is an essential step towards developing graphene-based spin-transfer torque magnetoresistive random access memory, quantum computing devices, magnonics and spintronic memory application

Area-elficient interlayer signal propagation in 3D IC by introducing electron spin

Through Silicon Via (TSV) is the major technology in order to transmit data among various devices in 3D IC. Therefore higher concentration of TSV is required for higher packing density in 3D IC. In order to obtain high density of TSV, the dimensions of TSV needs to be reduced. This may be achieved by increasing the surface area per layer which will benefit in packing of more components for any operation including logic implementation. In this paper we introduce electron spin rather than charge for the first time for interlayer signal transmission in 3D IC resulting in area efficiency. Ansys electromagnetic simulator (Maxwell 2D and 3D) and OOMMF simulation supported by theoretical analysis specifies an average of 90% area reduction per layer of 3D IC as compared to state-of-the art TSV

Shape-memory-alloy-based smart knee spacer for total knee arthroplasty: 3D CAD modelling and a computational study

This study introduced a shape memory alloy (SMA)-based smart knee spacer for total knee arthroplasty (TKA). Subsequently, a 3D CAD model of a smart tibial component of TKA was designed in Solidworks software, and verified using a finite element analysis in ANSYS Workbench. The two major properties of the SMA (NiTi), the pseudoelasticity (PE) and shape memory effect (SME), were exploited, modelled, and analysed for a TKA application. The effectiveness of the proposed model was verified in ANSYS Workbench through the finite element analysis (FEA) of the maximum deformation and equivalent (von Mises) stress distribution. The proposed model was also compared with a polymethylmethacrylate (PMMA)-based spacer for the upper portion of the tibial component for three subjects with body mass index (BMI) of 23.88, 31.09, and 38.39. The proposed SMA -based smart knee spacer contained 96.66978% less deformation with a standard deviation of 0.01738 than that of the corresponding PMMA based counterpart for the same load and flexion angle. Based on the maximum deformation analysis, the PMMA-based spacer had 30 times more permanent deformation than that of the proposed SMA-based spacer for the same load and flexion angle. The SME property of the lower portion of the tibial component for fixation of the spacer at its position was verified by an FEA in ANSYS. Wherein, a strain life-based fatigue analysis was performed and tested for the PE and SME built spacers through the FEA. Therefore, the SMA-based smart knee spacer eliminated the drawbacks of the PMMA-based spacer, including spacer fracture, loosening, dislocation, tilting or translation, and knee subluxation

Wettability of ZnO and curcumin decorated Graphene oxide nanocomposite for heavy metal ion removal from water

Hydrophilic nature of nanocomposite is essential for its efficient performance in water purification. The present work focusses on a) synthesis and characterization of graphene oxide- zinc oxide-curcumin (GO-Zn(cur)O) of varying concentration b) enhancing the hydrophilic nature by enhancing the number of functional groups embedded in graphene oxide and c) enhancing the antimicrobial properties by addition of curcumin. The composition of the nanocomposites has been systematically varied and the wettability has been studied. Characterization of the structure of the nanocomposites was done using X ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy. The hydrophilicity of GO-Zn(cur)O has been enhanced to 27.06° which would be beneficial for water purification. © 2022 IEEE

Temperature and Size Effect on the Electrical Properties of Monolayer Graphene based Interconnects for Next Generation MQCA based Nanoelectronics

Graphene interconnects have been projected to out-perform Copper interconnects in the next generation Magnetic Quantum-dot Cellular Automata (MQCA) based nano-electronic applications. In this paper a simple two-step lithography process for patterning CVD monolayer graphene on SiO2/Si substrate has been used that resulted in the current density of one order higher magnitude as compared to the state-of-the-art graphene-based interconnects. Electrical performances of the fabricated graphene interconnects were evaluated, and the impact of temperature and size on the current density and reliability was investigated. The maximum current density of 1.18 ×108 A/cm2 was observed for 0.3 μm graphene interconnect on SiO2/Si substrate, which is about two orders and one order higher than that of conventionally used copper interconnects and CVD grown graphene respectively, thus demonstrating huge potential in outperforming copper wires for on-chip clocking. The drop in current at 473 K as compared to room temperature was found to be nearly 30%, indicating a positive temperature coefficient of resistivity (TCR). TCR for all cases were studied and it was found that with decrease in width, the sensitivity of temperature also reduces. The effect of resistivity on the breakdown current density was analysed on the experimental data using Matlab and found to follow the power-law equations. The breakdown current density was found to have a reciprocal relationship to graphene interconnect resistivity suggesting Joule heating as the likely mechanism of breakdown

Self-healing phenomena of graphene: potential and applications

The present study investigates the self healing behavior of both pristine and defected single layer graphene using a molecular dynamic simulation. Single layer graphene containing various defects such as preexisting vacancies and differently oriented pre-existing cracks were subjected to uniaxial tensile loading till fracture occurred. Once the load was relaxed, the graphene was found to undergo self healing. It was observed that this self healing behaviour of cracks holds irrespective of the nature of pre-existing defects in the graphene sheet. Cracks of any length were found to heal provided the critical crack opening distance lies within 0.3-0.5 nm for a pristine sheet and also for a sheet with pre-existing defects. Detailed bond length analysis of the graphene sheet was done to understand the mechanism of self healing of graphene. The paper also discusses the immense potential of the self healing phenomena of graphene in the field of graphene based sub-nano sensors for crack sensing

Thermo-magnetic shape control of nano-ferromagnetic particle doped shape memory alloy for orthopedic devices and rehabilitation techniques

Recent advancement in smart materials facilitated the use of Shape Memory Alloy(SMA) in treatment of different orthopedic problems and rehabilitation technique to treat paralyzed patients. But Shape Memory alloy lacks the controllability while regaining the shape from martensite to austenite during thermal loading. Therefore, in this paper we introduced a mechatronic device which provides the control over the shape change of new hybrid material having property of SMA and shape memory property of anticipated material is verified by finite element analysis in COMSOL Multiphysics. In the proposed methodology the shape is controlled by generating a controlled thermo-magnetic loading, and hybrid material formed by doping a nano-ferromagnetic particle in porous NiTi SMA. For the proof of the concept an experiment is carried out by using a bimetallic strip, microcontroller, sensor and proper feedback circuitry system and it is observed that for the supply of 4V and bent angle for flex sensor between 0 to 40 degree, current through the solenoid is 3.63A producing Magnetic field of 1.42mT and for flex sensor b ent angle 4 0 to 7 5 degree the current through the solenoid is 1.2A producing Magnetic field of 0.47mT for same supply and if the flex sensor bent angle increases more than 75 degree then the voltage supply cutoffs which indicate the absence of Magnetic field

Microalbuminuria in hypertension and its relationship to target organ damage: A cross-sectional observational study in a tertiary hospital in Eastern India

Background: Microalbuminuria (MA) is an independent risk factor in association with fatal cardiovascular and cerebrovascular outcomes among patients with hypertension (HTN). Methods: An observational study was conducted among 100 randomly selected hypertensive patients January 2013 to January 2014 to observe the proportion of MA among hypertensive patients and the proportion of presence of various target organ damages (TODs) in them. Results: The frequency of MA was 36% among participants. The frequency in males was slightly more than females (38.2% vs. 33.3%). The frequency of MA increased linearly with the duration and severity of HTN. It was more commonly found in smokers than in non-smokers. Diastolic dysfunction (42%) and Grade 2 hypertensive retinopathy (60.7%) were associated with MA. TOD was frequently observed in MA-positive patients. Conclusions: The proportion of patients with MA was in increasing trend with increasing age of hypertensive participants and duration of history of HTN. Hypertensive retinopathy, regional wall motion abnormality and neurological deficit emerged to be sensitive surrogate markers for MA in patients with HTN