Aniruddha Ghosal

One‐dimensional hot‐electron transport in quantum‐well wires of polar semiconductors

The velocity‐field characteristics of hot electrons moving one dimensionally in the lowest subband of a polar semiconductor quantum‐well wire are obtained on a drifted Maxwellian model and also by the Monte Carlo technique. No negative differential resistance is obtained in contradiction to a previous prediction. The size effects at low temperatures are found to be more significant in the drifted Maxwellian model. Our calculations show that the one‐dimensional (1‐D) mobility for large transverse widths may be higher than the 3‐D mobility.

Design & study of a low power high speed full adder using GDI multiplexer

This paper proposes a new method for implementing a low power full adder by means of a set of Gate Diffusion Input (GDI) cell based multiplexers. Full adder is a very common example of combinational circuits and is used widely in Application Specific Integrated Circuits (ASICs). It is always advantageous to have low power action for the sub components used in VLSI chips. The explored technique of realization achieves a low power high speed design for a widely used subcomponent-full adder. Simulated outcome using state-of-art simulation tool shows finer behavioral performance of the projected method over general CMOS based full adder. Power, speed and area comparison between conventional and proposed full adder is also presented.

Fano resonance due to discrete breather in nonlinear Klein–Gordon lattice in metamaterials

The richer variety of Klein–Gordon basis is already established for discrete breathers in metamatetrials. Based on this attempt, we show various anomalous Fano resonance behaviors that have been experimentally observed, but cannot be explained by nonlinear Schrodinger model. Certain material parameters of Klein–Gordon lattice in metamaterials are related for the first time with characteristics of Fano resonance, which can be utilized for beam filtering and for high-resolution biological sensing technology. Although relations with coupling and other parameters exist, the most remarkable relation is observed with linear permittivity that could control the wave transmission characteristics in metamaterials for applications in optical engineering.

Bound to unbound state route and propagation of dark solitons showing acoustical memory

The dark and bright solitons in different systems are already known. If the intrinsic field is only considered, then the modal dynamics for small oscillations could be characterized by the bound state in a limited range of frequency, revealed via associated Legendre polynomial. The pairing and interplay between the dark and bright solitons occur. The disappearance of the bound state after a critical frequency gives rise to dark solitons in the unbound states that propagate through the domains. Above the upper boundary of the bound states, the estimated frequencies of dark solitons match with those experimentally found for ‘acoustical memory’.

Rectification of energy transport in nonlinear metamaterials via ratchets

The presence of discrete breathers (DBs) has already been described in nonlinear photonic materials, such as ferroelectrics and metamaterials (MMs) by the Klein?Gordon (K?G) approach. Rectification of energy transport in MMs in the presence of an appropriate external field is studied via symmetry breaking leading to directed energy transport or ratchet behaviour. Based on the earlier development of the K?G equation in a MM system with a split-ring resonator for antenna applications, a theoretical model for current density is worked out by symmetry analysis and its violation to characterize the ratchet effect. The time-averaged current shows interesting results against phase shift in the ac driver. These data are further related to various parameters, such as coupling and damping in the system. For MMs, this opens a new application for rectification using ratchets.

Design of a low power 4×4 multiplier based on five transistor (5-T) half adder, eight transistor (8-T) full adder & two transistor (2-T) AND gate

In this paper, we propose a new technique for implementing a low power high speed multiplier using full adder consisting of minimum no. of transistors (8-T). Multiplier circuits are used comprehensively in Application Specific Integrated Circuits (ASICs). Thus it is desirable to have high speed operation for the sub components. The explored method of implementation achieves a high speed low power design for the multiplier. Simulated results indicate the superior performance of the proposed technique over conventional CMOS multiplier. Detailed comparison of simulated results for the conventional and present method of implementation is presented.

Mobility of 1-D GaAs Quantum Wire Limited by Polar Optic Phonon Scattering

The polar optical phonon (POP) scattering limited mobility in 1-DEG quantum wire of GaAs has been investigated. The variation of mobility with well width for 1D GaAs quantum wire has been studied. The mobility dependence on the transverse dimension of quantum wire for different values of electron energy has been also been investigated. The results obtained at 300K for GaAs wire reveal that the variation is almost linear in nature

Advanced pioneer approach to various properties and significant parameters in special semiconductor arrangement

The paper numerically suggested the examination of potential energy profile at multibarrier system by using the Airy function formalism and consequently we derived the various transmission properties like transmission coefficient, reflection coefficient, energy and some other substantial physical parameters are analysed at different values of internal bias across the semiconductor arrangement.

Effects of scattering on transport properties in GaN

The mobility of the two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures changes significantly with Al content in the AlGaN layer and also determined from temperature-dependent Hall Effect measurements, while few mechanism analysis focus on it. Theoretical calculation and analysis of the 2DEG mobility in AlGaN/GaN heterostructures are carried out based on the recently reported experimental data. We have considered different scattering mechanism while calculating electron mobility, such as, polar optical phonon scattering, ionized impurity scattering, background impurity scattering. The result is that at low temperatures ion impurity scattering is the dominant scattering mechanism and at high temperatures polar optical phonon scattering is dominant. The variation of conductivity, drain current and power dissipation with temperature in AlGaN/GaN has been studied considering phonon interactions with electrons. The conductivity and power dissipation in AlGaN/GaN is highest at 80 Ks phonons.

Design and implementation of low power dual edge triggered flip-flop using GDI and TG for high speed FIR filter

In this paper, a technique for implementing low-power Dual Edge Triggered Flip Flop (DETFF) is introduced. Dual edge triggered flip flops has many advantages in low power VLSI compared to SETFF. The Proposed low power DETFF is implemented and compared with conventional DETFF at same simulation conditions. CAD tool based simulation and comparison between the non-conventional DET flip-flop with the conventional DETFF shows that the proposed DETFF reduces power dissipation by 66% reducing the no. of transistors used while keeping the same data rate.