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Goyal N.,Norwegian University of Science and Technology | Saxena R.S.,Solid State Physics Laboratory
IEEE Electron Device Letters | Year: 2013

We propose a new laterally diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET) with a tunneling junction at the drain side to reduce its on-state resistance and improve the peak transconductance significantly, as compared with the conventional LDMOSFET device. Using 2-D numerical simulations in an ATLAS device simulator, we have shown that the proposed tunneling junction at the drain side results in 25% reduction in RON and 20% improvement in peak transconductance in an ∼ 40-V device without any significant degradation in other performance parameters. © 2012 IEEE.

The structural and electrical properties of chemical-solution-deposited Bi1 - xSmxFeO3 (x = 0, 0.025, 0.05, 0.075, 0.1) thin films on Pt/Ti/SiOx/Si (100) substrates were investigated. Films up to 5 at.% Sm exhibited a single perovskite phase with rhombohedral structure, whereas films with 7.5 and 10 at.% Sm exhibited a distorted orthorhombic crystal structure. Atomic force microscopy of the films showed homogeneous and smooth surface. Films with 7.5 at.% Sm exhibited significant reduction in leakage current in the high electric field region and improved breakdown characteristic. The polarization vs. electric field (P-E) hysteresis loops were recorded in a 100 nm thick film with 3 V coercive voltages. Moreover, well saturated P-E hysteresis loops with high polarization (80 μC/cm 2) and low coercive field (300 kV/cm) were also recorded in 100 nm thick films with low coercive voltage (5 V). The Sm-substitution in BiFeO 3 improved the fatigue endurance with no significant degradation in polarization even after 108 fatigue cycles. These results demonstrate that Sm-substituted BifeO3 films have potential for application in low voltage operational device. © 2012 Elsevier B.V.

Saxena A.,Center for Fire Explosive and Environment Safety | Srivastava A.K.,Canadian Department of National Defence | Singh B.,Canadian Department of National Defence | Goyal A.,Solid State Physics Laboratory
Journal of Hazardous Materials | Year: 2012

Silica nanoparticles of diameter, 24-75nm and surface area, 875m 2/g were synthesized using aero-gel route. Thereafter, nanoparticles were impregnated with reactive chemicals, and used as reactive adsorbent to study the removal of toxic nerve and blister chemical warfare agents and their simulants from solutions. Trichloroisocyanuric acid impregnated silica nanoparticles showed the best performance and indicated physisorption followed by chemisorption/degradation of toxicants. This indicated their suitability as universal decontaminant for nerve and blister agents. This system showed a decrease in t 1/2 from 1210 to 2.8min for the removal of king of chemical warfare agents, i.e., sulphur mustard. Hydrolysis, dehydrohalogenation and oxidation reactions were found to be the route of degradation of toxicants over impregnated silica nanoparticles. © 2011 Elsevier B.V..

Rachna S.,Raja Ramanna Center for Advanced Technology | Bhattacharyya S.,Solid State Physics Laboratory | Gupta S.M.,Raja Ramanna Center for Advanced Technology
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

A correlated study involving structure analysis, temperature dependence of dielectric functions and the complex impedance spectroscopy analysis was carried out in lanthanum modified bismuth titanate (BT, Bi 4-xLa xTi 3O 12; x = 0, 0.75) ceramics. A series addition of three RQ circuits has been shown to remarkably fit the complex impedance data for both x = 0 and 0.75 samples, which were attributed to crystalline layer, plate boundary and grain boundary microelements. Temperature dependence DC-conductance of these microelements has revealed that lanthanum-ion substitution is mainly taking place in the perovskite blocks, which also led to decrease in orthorhombic splitting. This site preferred substitution was also consistent with shift in the oxygen ion-jump relaxation peak in the temperature dependence of the dissipation factor study. © 2010 Elsevier B.V.

Pahuja P.,University of Delhi | Prakash C.,Solid State Physics Laboratory | Tandon R.P.,University of Delhi
Ceramics International | Year: 2014

In this paper, effect of addition of Ni0.8Co 0.2Fe2O4 (NCF), prepared by three different methods namely solid state reaction method, sol-gel and co-precipitation, has been studied on microstructural, magnetic, dielectric, ferroelectric and magnetoelectric properties of multiferroic composite system 0.95 Ba 0.95Sr0.05TiO3-0.05 Ni0.8Co 0.2Fe2O4. Ba0.95Sr 0.05TiO3 (BST) has been prepared by solid state reaction method. Titular representation of NCF samples prepared by sol-gel, co-precipitation, solid state reaction method is N-SG, N-CP, N-SS respectively and that of corresponding magnetoelectric composite is C-SG, C-CP, C-SS. X-ray diffraction analysis of the composite samples (C-SG, C-SS, C-CP) indicated the presence of both NCF and BST phases. Rietveld analysis of XRD pattern further confirmed the proper phase formation in the composite samples. Sol-gel and co-precipitation processes result in finer NCF particles as confirmed by Transmission electron microscopy (TEM). Sample N-SG possesses uniform particle size and shape. Magnetization versus magnetic field (M-H) loops of samples C-SS and C-CP possess respectively highest value of remanant magnetization and magnetic coercive field. Dielectric properties of BST, NCF and composite samples have been measured in the frequency range of 20 Hz-1 MHz and temperature range of 50-170 C. The composite sample C-CP results in highest value of dielectric constant in comparison to samples C-SS and C-SG. Polarization versus electric field (P - E) measurements pointed that composite sample C-SG possesses highest value of remanant and saturation polarization and C-SS possesses lowest value of coercive electric field. The composite sample C-SS possesses highest value of magnetoelectric coefficient. © 2013 Elsevier Ltd and Techna Group S.r.l.

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