Highlights of IEEE Transactions on Nanotechnology (Vol. 14, No. 1, pp. 3-158, Jan. 2015). Fabrizio Lombardi, EiC.
1. Zidan, M.A. ; Omran, H. ; Sultan, A. ; Fahmy, H.A.H. ; Salama, K.N., Compensated Readout for High-Density MOS-Gated Memristor Crossbar Array. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 3-6, Jan. 2015.
Leakage current is one of the main challenges facing high-density MOS-gated memristor arrays. In this 
study, we show that leakage current ruins the memory readout process for high-density arrays, and analyze the tradeoff between the array density and its power consumption. We propose a novel readout technique and its underlying circuitry, which is able to compensate for the transistor leakage-current effect in the high-density gated memristor array.
2. Panagopoulos, G. ; Ho, C. ; Kim, S.Y. ; Roy, K., Physics-Based Compact Modeling of Successive Breakdown in Ultrathin Oxides. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 7-9, Jan. 2015.
In this letter, we present a physics-based compact SPICE model to predict statistical time-dependent dielectric breakdown (TDDB) in nanoscale circuits. In our model, an increase in the gate leakage current ( I_{G_{\rm BD}} ) induced by TDDB is estimated using a quantum point contact (QPC) model depending on temperature. In addition, I_{G_{\rm BD}} is based on the statistics of time to breakdown (BD) ( t_{{\rm BD}} ) and location of percolation path ( x_{{\rm BD}} ) in the channel considering third successive BDs. We show that the model can be easily implemented to circuit simulators to predict the degradation of circuit lifetime. With the proposed model, we validated post-BD I–V characteristics with experimental data in ultrathin oxide technology.
3. Son, K. ; Wong, D. ; Sharifi, H. ; Seo, H.C. ; De Lyon, T. ; Terterian, S. ; Moon, J.S. ; Hussain, T., Silver Nanowire-Based Infrared-Transparent Contacts for Future High-Density Format Focal Plane Arrays. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 10-14, Jan. 2015.
We report the first demonstration of: 1) wide-wavelength range, infrared transparent conductors (ITCs) made of silver nanowires (Ag NWs), and 2) ITC contact-integrated prototype, InAsSb mid-wavelength IR (MWIR) detectors. The Ag NW-based ITCs show optical transmittance ( Tλ) of ∼94% in the 0.9–2.5 μm wavelength range with a sheet resistance ( RS ) of 19.1 Ω/□. Tλ of the Ag NW-ITC decreases slowly with increasing wavelength, resulting in Tλ ∼92%–87% at 2.5–8 μm (MWIR) and Tλ ∼87%–82% at 8–15 μm (LWIR). The Ag NW-based ITC makes good ohmic contacts on InAsSb-based MWIR detectors with contact resistance of <0.5 Ω · mm. The ITC contact-integrated prototype InAsSb IR detectors are front-side illuminated and show external quantum efficiency (QE) of >85% at 4.25 μm and 150 K. The measured external QE remains at the same high level regardless of detector fill factor. These results indicate that Ag NW-ITCs may enable future pixel scaling for front-side illuminated, high-density-format focal plane arrays without compromising QE, responsivity, and detector performance.
4. Miranda, E. ; Mehonic, A. ; Blasco, J. ; Sune, J. ; Kenyon, A.J., Multiple Diode-Like Conduction in Resistive Switching SiOx-Based MIM Devices. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 15-17, Jan. 2015.
Filamentary conduction in resistive switching metal–insulator–metal devices is often modeled from the circuital viewpoint using diode-like structures with series resistances. We show in this letter which arrangement of diodes and resistances is compatible with experimental multilevel set and reset I–V characteristics in electroformed TiN/SiOx/TiN structures. The proposed model is based on the solution of the generalized diode equation corresponding to N diodes arranged in parallel with a single series resistance. The model is simple yet accurate and it is able to capture the essential features exhibited by the I–V curves in the low and high bias regimes, revealing that a single equation can deal with both the low and high resistance states. An exact expression for the differential conductance suitable for small-signal analysis and circuit simulators is also provided.
5. Chappanda, K.N. ; Smith, Y.R. ; Rieth, L.W. ; Tathireddy, P. ; Misra, M. ; Mohanty, S.K., Effect of Sputtering Parameters on the Morphology of TiO2 Nanotubes Synthesized From Thin Ti Film on Si Substrate. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 18-25, Jan. 2015.
In this paper, we present the analysis of the properties of direct current (dc) magnetron sputtered Ti thin film that affect the morphology of TiO2 nanotubes synthesized by electrochemical anodization. Si wafer with thermally grown silicon dioxide was used as the substrate for deposition of Ti films. By varying the properties of the sputtered film, morphology of the anodized film can be varied from tubular to nanoporous TiO2. Three sputtering parameters that affect the properties of the film were studied, which include sputtering power, process gas (argon) pressure, and substrate temperature. Anodization of these films was carried out at 30 V (dc) using an ethylene glycol-based electrolyte. We show that the properties of thin film such as grain size and residual stress (bi-axial) do not affect the morphology of the anodized film and density alone influences the morphology of the anodized film. Most of the applications demonstrated by TiO2 nanotubes require annealing at high temperatures (350–800 °C) for calcination. Low residual stress in the thin film is required to prevent delaminating of the nanotubes from the substrate when exposed to high temperatures. We demonstrate that by varying the sputtering parameters, Ti films with low stress can be deposited which is required to have stable TiO2 nanotubes or nanoporous structure, based on the requirement of the application.
6. Khedkar, G. ; Kudithipudi, D. ; Rose, G.S., Power Profile Obfuscation Using Nanoscale Memristive Devices to Counter DPA Attacks. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 26-35, Jan. 2015.
Side channel attacks (SCAs), such as differential power analysis (DPA), are considered as one of the most competent attacks to obtain the secure key of a cryptographic algorithm. Conventional countermeasures for DPAs are focused on hiding and masking techniques at different levels of design abstraction, associated with high power or area cost. However, emerging technologies such as resistive random access memory (RRAM), offer unique opportunities to mitigate SCAs/DPAs with their inherent device characteristics such as variability in write time, ultra low power (0.1–3 pJ/bit), and high density ($4F^2$). In this research, DPA attacks are mitigated by obfuscating the power profile using inverse RRAM modules. The state memory transaction power traces are balanced when the inverse memory is accessed in tandem with the memory module based on a peripheral balancing logic block. A baseline RTL architecture for the 128-bit AES cryptoprocessor is designed and implemented in CMOS technology. Balancing using RRAM and CMOS memory modules is compared against this baseline architecture. A customized simulation framework is developed for extracting the power traces using Synopsys and Cadence tool suites along with a Hamming weight DPA attack module implemented in Python. The attack mounted on the baseline architectures was successful and the full key was recovered. However, DPA attacks mounted on the inverse CMOS and RRAM-based AES cryptoprocessor yielded unsuccessful results with no keys recovered, demonstrating the resiliency of the proposed architecture against DPA attacks. More importantly, the power consumed with the RRAM balancing logic block is one order lower than the corresponding pure CMOS implementation.
7. Chen, S. ; Cui, Q. ; Guo, X., Annealing-Free Solution-Processed Silver Nanowire-Polymer Composite Transparent Electrodes and Flexible Device Applications. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 36-41, Jan. 2015.
By using ultrahigh aspect ratio (>2000:1) silver nanowires (AgNWs) and ethanol-diluted poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the overcoating layer, we achieved flexible AgNW-polymer composite transparent electrodes of high conductivity and optical transmittance using facile solution processes at room temperature without annealing. The electrodes were applied in fabricating flexible capacitive pressure sensors and organic photovoltaic (OPV) devices. The pressure sensor with the composite electrodes presents three times higher sensitivity than that using ITO electrodes. A flexible 4 x 4 sensor array was also fabricated, which well proved the capability of the electrodes for spatially electronic signal collection and transmission. The fabricated flexible OPV device has a power conversion efficiency of 1.83%, which proves the potential of the electrodes for multilayer integration in optoelectronic device applications
8. Ul Haq, R. ; Nadeem, S. ; Akbar, N.S. ; Khan, Z.H., Buoyancy and Radiation Effect on Stagnation Point Flow of Micropolar Nanofluid Along a Vertically Convective Stretching Surface. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 42-50, Jan. 2015.
Present model examines the 2-D boundary layer flow of natural convective micropolar nanofluid along a vertically stretching sheet. Moreover, we have considered the simultaneous effects of radiation and convective boundary surface. Influences of nanoparticles are also analyzed for both assisting and opposing flow. Similarity transformations are used to transform the governing nonlinear partial differential equation to ordinary differential equations. The condensed boundary layer equations for nanomicropolar fluid model are solved numerically. The effects of emerging parameters on velocity, temperature, and nanoparticle volumetric expansion profiles are discussed. Stimulating results are presented graphically and explained physically. The heat transfer rate and concentration rate are also displayed graphically for different flow control parameters.
9. Sengupta, A. ; Saha, D. ; Niehaus, T.A. ; Mahapatra, S., Effect of Line Defects on the Electrical Transport Properties of Monolayer MoS2 Sheet. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 51-56, Jan. 2015.
We present a computational study on the impact of line defects on the electronic properties of monolayer MoS2. Four different kinds of line defects with Mo and S as the bridging atoms, consistent with recent theoretical and experimental observations, are considered herein. We employ the density functional tight-binding (DFTB) method with a Slater–Koster-type DFTB-CP2K basis set for evaluating the material properties of perfect and the various defective MoS2 sheets. The transmission spectra are computed with a DFTB-non-equilibrium Green’s function formalism. We also perform a detailed analysis of the carrier transmission pathways under a small bias and investigate the phase of the transmission eigenstates of the defective MoS2 sheets. Our simulations show a two to four fold decrease in carrier conductance of MoS2 sheets in the presence of line defects as compared to that for the perfect sheet.
10. Tao, J. ; Wang, H. ; Lin, Q. ; Shen, H. ; Li, L.S., Quantum-Dot-Based Light-Emitting Diodes With Improved Brightness and Stability by Using Sulfuric Acid-Treated PEDOT:PSS as Efficient Hole Injection Layer. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 57-61, Jan. 2015.
Spin-coated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin film was treated with H2 SO4 and used as hole injection layer in quantum-dot-based light-emitting diodes (QD-LEDs). Such QD-LEDs with a H2SO4-treated PEDOT:PSS layer demonstrate improved carrier injection efficiency and luminance. Especially, the electroluminescence stability was greatly improved as well. Nearly 72% of peak luminance of QD-LEDs was preserved even after 24 h exposure in air for devices using H2SO4 -treated PEDOT:PSS film, while a rapid loss of 98% of peak luminance within a day for untreated devices was recorded. The improved performance for QD-LEDs with H2SO4-treated PEDOT:PSS film probably originated from the conformational change of the polymer chains and the removing of the insulating and hydrophilic PSS – bases from PEDOT:PSS layer. Such a simple but effective process may provide beneficial references for the development of high performance and long stability thin-film LEDs.
11. Wang, X. ; Zhao, W. ; Hu, J. ; Yin, W., Reconfigurable Terahertz Leaky-Wave Antenna Using Graphene-Based High-Impedance Surface. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 62-69, Jan. 2015.
The concept of graphene-based two-dimensional leaky-wave antenna (LWA), allowing both frequency tuning and beam steering in the terahertz band, is proposed in this paper. In its design, a graphene sheet is used as a tuning part of the high-impedance surface (HIS) that acts as the ground plane of such 2-D LWA. It is shown that, by adjusting the graphene conductivity, the reflection phase of the HIS can be altered effectively, thus controlling the resonant frequency of the 2-D LWA over a broad band. In addition, a flexible adjustment of its pointing direction can be achieved over a wide range, while keeping the operating frequency fixed. Transmission-line methods are used to accurately predict the antenna reconfigurable characteristics, which are further verified by means of commercial full-wave analysis tools.
12. Choi, W. ; Seo, Y. ; Park, J. ; Kim, K.B. ; Jung, J. ; Lee, N. ; Seo, Y. ; Hong, S., Effect of Annealing in Ar/H2 Environment on Chemical Vapor Deposition-Grown Graphene Transferred With Poly (Methyl Methacrylate). IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 70-74, Jan. 2015.
Poly(methyl methacrylate) (PMMA) is widely used for transferring chemical vapor deposition grown graphene. The residue of PMMA after the transfer degrades the electronic properties of the graphene, and the complete removal of PMMA has been a challenging issue. Annealing in Ar/H2 gas flow has been commonly adopted to remove the PMMA residue. We studied the effect of annealing on graphene in the wide temperature range of 350–800 °C using Ar/H2 forming gas, systematically. The conductivity was increased at moderate temperatures, but decreased at excessive temperatures higher than 650 °C. On the other hand, the PMMA residue was not removed effectively in all temperature ranges, judging from Raman spectroscopy and atomic force microscopy. By analyzing Raman spectroscopic data, chemisorption of PMMA residue on graphene was confirmed.
13. Farmahini-Farahani, M. ; Mosallaei, H., Functional-Graded Index Metasurfaces for Infrared Radiation and Guiding. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 75-81, Jan. 2015.
We present the fundamental principle of plasmonic-graded-index materials for radiating and guiding at infrared range. The method to derive effective refractive index is presented and effective refractive index engineering is comprehensively investigated by obtaining complex dispersion diagrams. As an illustrative example for radiating structure, a graded index metasurface is designed for collimating the power emanating from an aperture to a steered narrow beam. The center frequency of operation is 57.5 THz. The half power beam widths of the beam radiated from a 15λ x 15λmetasurface to θ= 30 ° direction are 6° and 16° in elevation and azimuth planes, respectively. Radiation efficiency is calculated to be 86%. To demonstrate the guiding application, a flat step index waveguide is designed. The surface wave guiding is characterized by obtaining complex dispersion diagram and mode profiles. The applications of such waveguides in feeding antennas and routing surface waves are demonstrated with some unique designs.
14. Qi, N. ; Fang, Y. ; Ren, X. ; Wu, Y., Varying-Gain Modeling and Advanced DMPC Control of an AFM System. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 82-92, Jan. 2015.
For an atomic force microscope (AFM) system equipped with a nanosensor, an accurate varying-gain dynamic model is obtained when considering the piezoscanner bending effect, which is then utilized to design an advanced discrete-time model-predictive controller (DMPC) achieving accurate tracking performance for any given trajectory. Specifically, considering the features of the piezoscanner in the AFM system, a segmented swept signal with decreasing amplitudes is adopted as the input exerted on the piezoscanner, with the collected data utilized to set up a dynamic model based on the numerical algorithm for subspace state-space system identification (N4SID) algorithm, where the varying gain is successfully acquired by a polynomial fitting method to increase model precision. Based on the predicted dynamic behavior of the varying-gain model, an advanced DMPC algorithm is designed to fasten the system response and to enhance the robustness of the closed-loop system. The proposed modeling/control strategy is implemented and then applied to a practical AFM system, with the obtained experimental results clearly demonstrating the superior performance of the designed AFM closed-loop control system.
15. Nagy, D. ; Elmessary, M.A. ; Aldegunde, M. ; Valin, R. ; Martinez, A. ; Lindberg, J. ; Dettmer, W.G. ; Peric, D. ; Garcia-Loureiro, A.J. ; Kalna, K., 3-D Finite Element Monte Carlo Simulations of Scaled Si SOI FinFET With Different Cross Sections. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 93-100, Jan. 2015.
Nanoscaled Si SOI FinFETs with gate lengths of 12.8 and 10.7 nm are simulated using 3-D finite element Monte Carlo (MC) simulations with 2-D Schrödinger-based quantum corrections. These nonplanar transistors are studied for two cross sections: rectangular-like and triangular-like, and for two channel orientations: ‹100› and‹110›. The 10.7-nm gate length rectangular-like FinFET is also simulated using the 3-D nonequilibrium Green’s functions (NEGF) technique and the results are compared with MC simulations. The 12.8 and 10.7 nm gate length rectangular-like FinFETs give larger drive currents per perimeter by about 33–37% than the triangular-like shaped but are outperformed by the triangular-like ones when normalised by channel area. The devices with a ‹100›channel orientation deliver a larger drive current by about 11% more than their counterparts with a ‹110› channel when scaled to 12.8 nm and to 10.7 nm gate lengths. ID-VG characteristics obtained from the 3-D NEGF simulations show a remarkable agreement with the MC results at low drain bias. At a high drain bias, the NEGF overestimates the on-current from about VG-VT=0.3$ V because the NEGF simulations do not include the scattering with interface roughness and ionized impurities.
16. Huang, C. ; Tian, X. ; Liu, J. ; DONG, Z. ; Wang, Y., The Assembly and Fabrication of Single CuO Nanowire Electronic Device Based on Controllable DWS-DEP Technology. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 101-107, Jan. 2015.
CuO nanowire is an important one-dimensional semiconductor material to assemble and fabricate novel nanoelectronic device, especially molecular or atom device based on single nanowire. However, how to assemble and fabricate nanoelectronic device based on single CuO nanowire remains a big challenge. Here, we proposed a new controllable dielectrophoresis assembly technology, namely dielectrophoretic working space-dielectrophoresis technology, to realize the assembly and fabrication of single CuO nanowire nanoelectronic device. Theoretical analysis and assembly experiments verified the effectiveness of the new technology. By this technology, currently we have successfully fabricated two kinds of single CuO nanowire nanoelectronic device, photodetector and alcohol sensor, from CuO nanowire’s preparation, dispersion to assembly. Due to the high sensitivity of single CuO nanowire, the novel alcohol sensor can work at room temperature compared to the CuO nanowires arrays-based sensor working only at high temperature. The proposed technology can also be utilized to assemble and fabricate single-nanowire electronic device based on other materials.
17. Ravichandran, A.T. ; Dhanabalan, K. ; Vasuhi, A. ; Chandramohan, R. ; Mantha, S., Morphology, Bandgap, and Grain Size Tailoring in Cu2O Thin Film by SILAR Method. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 108-112, Jan. 2015.
Copper Oxide thin films have been deposited onto glass substrate with different time for 30 cycles by successive ionic layers by adsorption and reaction method. The layers were grown with different immersion times such as 15, 20, 25, and 30 s, respectively, employing copperthiosulphate aqueous solutions. Crystal phases were attained in all dipping levels. Copper oxide is one of the most promising candidates for nonstoichiometric p-type transparent semiconducting oxide materials. Fourier transformation infrared spectroscopy studies confirmed the formation of copper oxide and the characteristic vibrational mode of CuO was identified. Both the structural and surface properties of copper oxide thin films were improved with increase in the deposition time as a result of which the optical absorption edge of copper oxide shifts toward longer wavelengths, the optical bandgap energy vary from 1.43 to 1.96 eV. The crystallinity of the film is high with allow the maximum nucleation process. The room temperature photoluminescence spectrum has also been taken to elucidate the optical emission properties of these thin films.
18. Wang, X. ; Zhao, J. ; Wang, X. ; Zhou, J., Causes for the Formation of Titania Nanotubes During Anodization. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 113-117, Jan. 2015.
Titania nanotube arrays were prepared in the electrolyte containing dimethyl sulphoxide and HF through anodization method and the morphology and composition of the nanotube arrays were characterized through scanning electron microscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The causes for the formation of nanotubes have been discussed according to the experimental results. Nanopores are formed firstly at the early stage of anodization, O2− ion needed to oxidize the titanium metal below the pore wall must diffuse inward from both sides of the pore wall. Because of the different diffusion resistances, O2− concentrations are different at different positions of the interface between titanium metal and pore wall, leading to different oxide compositions. As a result, the surface of pore wall is mainly composed of high valence oxide TiO2, while the middle of pore wall is mainly composed of suboxides, such as Ti2O3 and TiO. The pore wall would crack easily at the middle low strength suboxides due to temperature changes during anodization, which results in the conversion of nanopores into nanotubes. The selective dissolution of suboxides in the electrolyte leads to the formation of gaps between nanotubes.
19. Rahman, R. ; Servati, P., Efficient Analytical Model of Conductivity of CNT/Polymer Composites for Wireless Gas Sensors. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 118-129, Jan. 2015.
This paper presents an analytical model of conductivity and sensitivity of passive wireless sensors for biohazard gas detection with lower computational cost and reasonable accuracy. Based on the effect of electron tunneling among the carbon nanotubes embedded in a polymer matrix, an analytical model for conductivity of the composite is presented. This model provides significantly lower computational cost as compared to the numerical resistive network models. By incorporation of electron tunneling effects, this model also provides closer approximation to experimental results in comparison to the models based on the percolation theory, which are highly relevant for filler/polymer composite applications designed around the percolation threshold. Using this conductivity model, the conductivity and sensitivity of the composite films are estimated in the presence of an organic gas. The change in the film resistance due to the absorption of the gas is investigated for different filler and gas concentrations. From the phase of the reflected radio frequency signal, the applications of the sensor for passive wireless gas sensing is estimated in a lossless transmission system terminated with a composite film as the load. This paper is useful for design and development of biohazard gas sensors for real-time remote monitoring.
20. Li, G. ; Mathew, J. ; Shafik, R.A. ; Pradhan, D.K. ; Ottavi, M. ; Pontarelli, S., Lifetime Reliability Analysis of Complementary Resistive Switches Under Threshold and Doping Interface Speed Variations. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 130-139, Jan. 2015.
Complementary resistive switching (CRS) memristor is an emerging nonvolatile memory device that features low-sneak path current compared to traditional memristors. Despite its advantages, threshold voltage and doping interface drift speed variations over time are major concerns for CRS memory devices. In this paper, we will demonstrate that these variations can significantly reduce the CRS lifetime reliability in terms of number of memory operations that can be performed. Based on such demonstrations, comprehensive theoretical and empirical studies are carried out using H-Spice based simulations to investigate the impact of biasing and threshold voltages on CRS lifetime reliability. Underpinning these studies, a novel CRS lifetime relationship is proposed and extensively validated through further simulations.
21. Manohar, S.K. ; Venkatasubramanian, R. ; Balsara, P.T., Heterogeneous NEMS-CMOS DCM Buck Regulator for Improved Area and Enhanced Power Efficiency. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 140-151, Jan. 2015.
In CMOS switches, the input signal modulates the on-channel resistance for a constant gate voltage. This necessitates over design of CMOS switches. Also, further CMOS scaling in the nanometer regime has failed to improve energy efficiency due to increasing leakage energy. Looking beyond CMOS, nanoelectromechanical (NEM) relays are a promising class of emerging devices that exhibit energy-efficient switching and zero leakage operation. Ron of the NEM relay switch is constant and is insensitive to the gate slew rate. This creates a paradigm shift in design of power switches. This coupled with infinite Roff offers significant area and power advantages over CMOS. Numerous end applications of NEM relay logic circuits have been proposed recently, including digital logic and memory. NEMS-based miniature switches form an interesting alternative in power management integrated circuits, the area of which is primarily dominated by CMOS power transistors. This study explores discontinuous-conduction mode buck regulator with specifications suitable for portable applications using a NEMS-CMOS hybrid design, and the results are compared against a standard commercial 0.35μm CMOS implementation. The electromechanical model has been developed for a suspended gate relay operating at 1 V with a nominal air gap of 5-10 nm published in the literature. The model accounts for the mechanical, electrical, and dispersion effects in the relay. This study shows that NEMS-CMOS hybrid dc–dc converter has an area savings of 60% over CMOS and achieves an overall higher efficiency over CMOS, with a peak efficiency of 94.3% at 100mA.
22. Kyatsandra, S. ; Wilkins, R.,Total Ionizing Dose X-ray Radiation Effects on MWCNT/PMMA Thin Film Composites. IEEE Transactions on Nanotechnology, Vol. 14, No. 1, pp. 152-158, Jan. 2015.
Multiwalled carbon nanotube (MWCNT) and poly(methyl methacrylate) (PMMA) composites are a new class of nanomaterial composites that have potential to be deployed as sensing elements for various applications including ionizing radiation detection. In this paper, we present an investigation of the ionizing radiation effects on electrical resistance of this composite both from a dose and dose rate standpoint. The solution blending method was used in synthesizing the MWCNT/PMMA composites. The synthesized thin film composites were cast on an interdigitated electrode to perform radiation sensing experiments. A 160-kV X-ray radiation source was used to study the ionizing radiation effects on the synthesized composite. A carbon black/PMMA composite was synthesized and subjected to the same dose and dose rate experiments as the MWCNT/PMMA thin film composite and a comparison was made. We have observed a very good repeatable quasi-linear response curve for radiation dose and dose rate measurement with the MWCNT/PMMA composite. Post radiation exposure recovery time of MWCNT/PMMA composite and heat treatment technique to accelerate recovery time have also been studied and the results are presented. The results suggest that simple sensor elements based on relatively economical MWCNT may be useful for the detection of ionizing radiation.
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