T. Sahu

Berhampur university · Department of Electronic Science

A new design is proposed for the realization of graphene metamaterials with enhanced robustness and absorption in the THz regime. The design uses the concept of embedding holes into a bilayer graphene sheet, which effectively works like a conventional fishnet-shaped metamaterial structure with better absorptance and spectral response features. Abso...

The effect of tensile and compressive strain on low‐temperature electron transport ( τ t ) and quantum ( τ q ) lifetimes are analyzed as function of well width ( w ) in In x Ga 1− x As/In 0.52 Al 0.48 As modulation‐doped double quantum well (MD‐DQW)‐based high electron mobility transistors structures. The DQW system can be made either lattice‐match...

We study the effect of asymmetric doping concentrations on the electron mobility µ in GaAs/InGaAs-based single quantum well (SQW) as well as double quantum well (DQW) pseudomorphic high electron mobility transistor (pHEMT) structures. Unequal doping in the substrate and surface barriers (nd1 and nd2) causes asymmetric distributions of subband wave...

The mobility, µ of electrons shows oscillating behavior in an asymmetric GaAs/InxGa1-xAs Quantum Well (QW) Field Effect Transistor (FET) structure. So as to analyze µ, we take asymmetric doping concentrations, varying Nd1 in the substrate barrier and keeping Nd2 constant in surface barrier. The well widths W1 and W2 are also asymmetrically changed...

Here, we analyse the effect of structure parameters like well width (w), central barrier width (b), and alloy concentration (x) on multisubband electron mobility µ in a GaAs-AlxGa1-xAs based modulation doped asymmetric V-shaped-double-quantum-well (VDQW) structure. The asymmetry in the structure potential is generated through the difference in the...

The improvement of transport electron mobility μ is theoretically reported through a change in well width w in an asymmetric V-shaped double quantum well (AVDQW) structure. The side barriers are doped with different doping concentrations i.e., N d1 (vary) and N d2 (fixed) towards the substrate and surface respectively which produces asymmetry in th...

Nonmonotonic electron mobility is obtained in InxGa1-xAs/GaAs double quantum well pseudomorphic heterostructure field effect transistor by changing the structure parameters. We show that a rapid drop in mobility occurs at the point of resonance of sub-band states due to asymmetric variation of doping concentrations. The sub-band wave function distr...

The nonlinear electron mobility µ is obtained in an asymmetric doped V-shaped double quantum well field-effect transistor (FET) structure based on AlxGa1-xAs. The nonmonotonic oscillation of µ occurs owing to intersubband interactions through the ionized impurity scattering when two subbands are occupied. The magnitude of µ is dominated by the allo...

The effect of asymmetric doping profile on the electron mobility μ is studied in a Field Effect Transistor (FET) structure based on AlxGa1−xAs double V-shaped quantum well (D-VQW) in presence of an external electric field F. We introduce asymmetry in the structure by considering different doping concentrations in the side barriers along the substra...

We analyze the electron mobility μ of GaN / AlGaN based quantum well (QW) transistor structure. We consider the potential profile V ( z ) by including the potential due topolarization ( V p ) and Hartree potential ( V H ) owing to surface electron density N s . The low temperature mobility is governed by the alloy disorder ( ad- ) and interface rou...

We study the electron transport in armchair graphene nanoribbon (AGNR) resonant tunneling diode (RTD) using square and V-shaped potential well profiles. We use non-equilibrium Green’s function formalism to analyze the transmission and I-V characteristics. Results show that an enhancement in the peak current ( I p ) can be obtained by reducing the w...

In this paper, we study the nonlinear channel electron mobility μ in an asymmetrically doped double quantum well field-effect transistor (QWFET) structure. The double quantum well consists of V-shaped channels by tailoring the conduction band edge of AlxGa1−xAs alloy through suitable variation of the alloy concentration x. We vary the widths of the...

Non-monotonic mobility μ of electrons is obtained in a pseudomorphic GaAs/InxGa1−xAs high electron mobility transistor having double quantum well structure with asymmetric doping concentrations in the outer barriers. A dip in μ occurs close to the resonance of subband states because of the quantum mechanical transfer of the wave functions between t...

In this work, we present theoretically the effect of external electric field Fe on low temperature multisubband electron mobility μ in V-shaped double quantum well (V-DQW) HEMT structure. We consider the impact of ionised impurity and alloy disorder scatterings for the calculation of μ. We show that, in the proposed structure, when Fe, is absent, t...

We analyze the asymmetric delta-doping dependence of nonlinear electron mobility μ of GaAs|In x Ga 1-x As double quantum-well pseudo-morphic modulation doped field-effect transistor structure. We solve the Schrodinger and Poisson's equations self-consistently to obtain the sub-band energy levels and wave functions. We consider scatterings due to th...

We study the effect of the external electric field Fext on the low-temperature electron mobility μ in an asymmetrically doped AlxGa1-xAs based V-shaped double quantum well (VDQW) structure. We show that nonlinearity of µ occurs under double subband occupancy on account of intersubband effects. The field Fext alters the VDQW potential leading to tra...

We show that the enhancement of electron mobility μ as function of well width w can be achieved in a GaAs/Alx Ga1-xAs square-parabolic double quantum well (SPDQW) high electron mobility transistor (HEMT) structure. We consider the structures, in which one of the square well lies towards the substrate (SPDQW), and in another towards the surface (PSD...

Herein, it is shown that the oscillation of low temperature electron mobility μ can be obtained as a function of external electric field F in AlxGa1−xAs based V‐shaped double quantum well (VQW) structure. The oscillation of μ can be enhanced by increasing the well width and barrier width as well as decreasing the doping concentration and height of...

We study the effect of parabolic potential on the improvement of low temperature multisubband electron mobility µ in a GaAs/AlxGa1-xAs hybrid double quantum well (HD) structure. The HD consists of a square and another parabolic well towards the bottom and top surfaces of the structure respectively. We calculate µ as function of well width w by cons...

We study the effect of asymmetric potential profile on the electron mobility µ of a double quantum well (DQW) structure. In a DQW, along with confinement effect, the coupling of subband states between the wells further splits the energy levels thereby acting as an additional degree of freedom to regulate the subband electron structure properties. W...

We study the impact of non-square potential well structure on the electron mobility μ of double quantum well (DQW) based field effect transistors carved out of the AlxGa1-xAs alloy. The barriers lying towards the substrate and surface sides of the DQW are delta doped with Si. We consider DQWs having V-shaped (VDQW), parabolic (PDQW), cubic (CDQW) a...

The nonlinearity of multisubband electron mobility µ in a GaAs/AlxGa1−xAs wide quantum well structure is studied by varying the well width w and doping concentration Ndb (Ndt ) lying in the bottom (top) barrier. The electrons diffuse into the well and accumulate near the interfaces forming two sheets of coupled two dimensional electron gases equiva...

We study enhancement of electron mobility in a MODFET by suggesting a hybrid double quantum well (HDQW) structure where one of the wells is square type while the other is parabolic. We consider the wells are of equal width w with side barriers being delta doped symmetrically. We analyze μ as function of w by considering double subband occupancy in...

We study the enhancement of multisubband electron transport mobility μ as function of well width w of AlxGa1−xAs based square — parabolic double quantum well (SPDQW) in which the side barriers are delta doped with Si. We calculate μ by considering different elastic scatterings. We show that when single subband is occupied μ is mostly governed by in...

We study the asymmetric doping dependence of electron mobility µ in an AlxGa1−xAs based square-parabolic double quantum well (SPDQW) high electron mobility transistor (HEMT) structure. We consider the square (parabolic) well and doping concentration Nd1 (Nd2) in the barrier toward the substrate (surface) of the structure. Keeping Nd1 fixed, variati...

We analyze the structural-asymmetry-induced nonlinear enhancement of the electron mobility μ in a GaAs/InxGa1%xAs double-quantum-well pseudomorphic high-electron-mobility transistor (p-HEMT). We consider the well widths wi and ws and the doping concentrations ndi and nds in the barriers along the substrate (inverted doping) and surface (surface dop...

We study the enhancement of electron mobility μ in barrier delta-doped GaAs/AlGaAs quantum-well-based modulation-doped field-effect transistor (MODFET) structures. We asymmetrically vary the doping concentrations Nd1 and Nd2 in the barriers on the substrate and surface sides, respectively, to obtain a nonlinear enhancement of μ as a function of the...

We show that higher multisubband electron mobility μ can be achieved in AlxGa1-xAs based hybrid type square-parabolic asymmetric double quantum well (HDQW) compared to that of the symmetric square double quantum well (SDQW) and parabolic double quantum well (PDQW) structures. We show that μ(HDQW) > μ(PDQW) > μ(SDQW). This trend in the enhancement o...

Background: Leukemia is the most prevalent childhood cancer. Acute lymphoblastic leukemia (ALL) constitutes 75% of all cases. Objective: To find out the most common clinical and hematological findings of pediatric patients with acute leukemia at a tertiary care center of central India. Materials and Methods: This retrospective study was done on 30...

We have studied the modulation of electron mobility μ as a function of the electric field perpendicular to the interface plane Fp in a GaAs/AlGaAs double quantum well structure near the resonance of subband states. The functional dependence of μ on Fp exhibits a minimum near the anticrossing of subband states leading to an oscillatory behaviour of...

In this work, we analyze the effect of coupling of subband wave functions through central barrier on nonmonotonic behavior of electron mobility (µ) in a double quantum well structure. The doping is done only on the substrate side of the structure. The subband energy levels and wave functions of the double quantum well are obtained through selfconsi...

We analyze the effect of applied electric Field F on low temperature multisubband electron mobility μ of GaAs-AlxGa1-xAs coupled double quantum well structure in which the side barriers are delta doped with Si. We show that when one of the side barriers is doped, the occupation of subbands changes from single subband to double and then again to sin...

We study the effect of applied electric field F on low temperature electron mobility μ in an AlxGa1-xAs parabolic quantum well structure in which one of the side barriers (left) is delta doped with Si. We consider ionized impurity (ii-) scattering and alloy disorder (ad-) scattering to analyze μ as a function of F. We show that there is linear rise...

We present the effect of asymmetry in doping concentrations on the low temperature electron mobility (µ) in a barrier delta (δ)-doped AlGaAs/GaAs coupled double quantum well structure considering more than one subband occupancy. The subband energy levels and wave functions of the structure are obtained by selfconsistent solution of Schrödinger and...

We elucidate the effect of asymmetry in well widths on the nonmonotonic oscillating behavior of electron mobility (µ) under double subband occupancy in AlGaAs/GaAs coupled quantum well structures. We adopt selfconsistent solution of Schrödinger and Poisson’s equations to obtain the subband energy levels and wave functions of the double quantum well...

We study the effect of applied electric field F on low temperature electron mobility μ in a GaAs/AlxGa1-xAs coupled double quantum well structure by varying the doping concentrations Nd1 and Nd2 lying in the barriers towards the substrate and surface sides respectively. We consider ionized impurity scattering, alloy disorder scattering and interfac...

We show that sharp nonmonotic variation of low temperature electron mobility μ can be achieved in GaAs/AlxGa1-xAs barrier delta-doped double quantum well structure due to quantum mechanical transfer of subband electron wave functions within the wells. We vary the potential profile of the coupled structure as a function of the doping concentration i...

We study the effect of coupling of subband wave functions on the multisubband electron mobility in a barrier delta doped GaAs/AlxGa1-xAs asymmetric double quantum well structure. We use selfconsistent solution of the coupled Schrödinger equation and Poisson's equation to calculate the subband wave functions and energy levels. The low temperature mo...

We show that nonmonotonic enhancement of low temperature electron mobility μ can be achieved in GaAs/AlxGa1-xAs barrier delta doped double quantum well structure under double subband occupancy. We vary the well widths asymmetrically by shifting the position of the central barrier and analyze its effect on the multisubband electron mobility taking d...

We analyse the effect of asymmetry in the structure parameters on low-temperature multisubband electron mobility μ in a barrier delta-doped GaAs/AlGaAs double quantum well structure. We obtain the subband energy levels and wave functions through self-consistent solution of Schrodinger and Poisson's equations. We show that μ is enhanced through asym...

Weshow that oscillation of low temperature electron mobility l can be achieved in a single side barrier delta doped asymmetric GaAs/ AlxGa1�xAs double quantum well structure. By applying an external electric field F the potential structure can be varied. Accordingly the system undergoes changes from single subband occupancy to double and then again...

Westudytheeffectofcouplingofsubbandwavefunctionsonthemultisubbandelectronmobilityina barrier deltadopedGaAs/AlxGa1�xAs asymmetricdoublequantumwellstructure.Weuseselfconsistent solution ofthecoupledSchrödingerequationandPoisson'sequationtocalculatethesubbandwave functions andenergylevels.Thelowtemperaturemobilityisconsideredbyusingscatteringsdueto i...

We show that oscillation of low temperature electron mobility μ can be obtained by applying an electric field F along the growth direction of the asymmetrically barrier delta doped Al xGa 1-x As parabolic double quantum well structure. The drastic changes in the subband Fermi energies and distributions of subband wave functions as a function of...

We analyse the low temperature multisubband electron mobility in an AlxGa1-xAs parabolic quantum well in which the side barriers are delta doped with Si. We change the doping profile and other structure parameters to study their effect on the electron mobility mu through intersubband effects. We show that with increase in surface electron density N...

We study the effect of external electric field F on the multisubband electron mobility μ of a barrier delta doped AlxGa1−xAs parabolic quantum well structure. We show that by applying the electric field a transition from double subband to single subband occupancy can be made leading to enhancement of mobility due to supression of intersubband effec...

The effect of external electric field F on multisubband electron mobility μ in an In0.53Ga0.47As/In0.52Al48As double quantum well structure is analyzed. We consider scatterings due to ionized impurities, interface roughness and alloy disorder to analyze μ. The variation of scattering mechanisms as a function of F for different structure parameters...

We study the enhancement of electron mobility through structural asymmetry of a delta doped GaAs/AlxGa1−xAs coupled quantum well structure. We obtain the subband energy levels and wave functions through selfconsistent solution of the Schrodinger equation and the Poisson's equation. We calculate the low temperature electron mobility by considering s...

For the first time, we show that an oscillatory enhancement of low temperature electron mobility μ can be achieved in an asymmetric GaAs/AlxGa1−xAs wide quantum well structure by applying an external electric field F perpendicular to the interface plane. We show that the oscillating nature of μ as a function of F is mostly due to the contribution o...

We study the low temperature multisubband electron mobility in a structurally asymmetric GaAs/AlxGa1-xAs delta doped double quantum well. We calculate the subband energy levels and wave functions through selfconsistent solution of the coupled Schrodinger equation and Poisson's equation. We consider ionized impurity scattering, interface roughness s...

We propose a novel technique to measure the concentration of sucrose in PAm-hydrogel sucrose solution using two dimensional photonic crystal structures consists of air holes. PAm-hydrogel is an organic hydrogels, which is used as biomedical applications. The principle of measurement is based on the linear variation of photonic band gap with the cha...

We analyze the enhancement of multisubband electron mobility in delta-doped Al x Ga 1-x As parabolic quantum well structures. We show that mobility is considerably enhanced in a parabolic quantum well compared to that in a square quantum well due to shifting of subband electron wave functions towards the centre of the well through the influence of...

We study the multisubband electron mobility in a barrier delta doped AlxGa1−xAs parabolic quantum well structure under the influence of an applied electric field perpendicular to the interface plane. We consider the alloy fraction x = 0.3 for barriers and vary x from 0.0 to 0.1 for the parabolic well. Electrons diffuse into the well and confine wit...

The effect of structural asymmetry on multisubband electron mobility is studied by considering a barrier delta doped GaAs/AlxGa1�x As quantum well structure. The subband wave functions and energy levels are obtained by adopting selfconsistent solution of the coupled Schrodinger and Poisson’s equations. We consider scatterings due to ionized impurit...

The effect of structural asymmetry on multisubband electron mobility is studied by considering a barrier delta doped GaAs/AlxGa1�x As quantum well structure. The subband wave functions and energy levels are obtained by adopting selfconsistent solution of the coupled Schrodinger and Poisson’s equations. We consider scatterings due to ionized impurit...

We study the effect of external electric field F on the multisubband electron mobility � of a barrier delta doped AlxGa1-xAs parabolic quantum well structure. We show that by applying the electric field a transition from double subband to single subband occupancy can be made leading to enhancement of mobility due to supression of intersubband effec...

We analyze the electron mobility in asymmetric double quantum wells by introducing different doping concentrations in the barriers and also by taking different well widths. We show that the asymmetry induced changes in the subband wave functions, energy levels and occupation of subbands lead to enhancement in subband mobility in a multisubband occu...

We study the effect of parabolic potential well profile on the electric field dependent multisubband electron mobility in a double quantum well structure. We consider a barrier delta doped GaAs-AlxGa1-xAs parabolic coupled double quantum well subject to an external electric field perpendicular to the interface plane. Variation of the electric field...

We analyze the low temperature multisubband electron mobility in AlxGa1−xAs–GaAs parabolic double quantum well structures in which the outer barriers are delta doped with Si. The structural parabolic potential, obtained from gradual variation of the alloy fraction x (from 0 to xp), partly compensates the triangular like potential profile near the o...

The effect of structural asymmetry on multisubband electron mobility is studied by considering a barrier delta doped GaAs/AlxGa1-x As quantum well structure. The subband wave functions and energy levels are obtained by adopting selfconsistent solution of the coupled Schrodinger and Poisson’s equations. We consider scatterings due to ionized impurit...

We calculate multisubband electron mobility in a AlxGa1-xAs parabolic double quantum well structure. The wells are formed by varying x from 0 to 0.1. For barriers we take x=0.3. The side barriers are delta-doped with Si. The electrons diffuse into the adjacent wells inducing triangular like potential profiles near the interfaces. The structural pot...

We analyse the effect of parabolic potential profile on the multrisubband electron mobility in a GaAs-AlGaAs parabolic double quantum well structure. We show that in case of a double quantum well structure, the mobility is enhanced at large well widths at which two subbands are occupied. On the other hand for a single parabolic quantum well, the oc...

We study the effect of external electric field F in enhancing the multisubband electron mobility mediated by intersubband effects in a pseudomorphic GaAs / InxGa1-xAs coupled double quantum well structure. An electric field F changes the potential profile of the structure which in turn amends the subband energy levels and wave functions. By varying...

We analyze the enhancement of multisubband electron mobility due to an external electric field in a pseudomorphic GaAs/InxGa1-xAs coupled double quantum well structure. An electric field, applied perpendicularly to the interface plane, changes the potential energy profile of the structure. This change alters the energy level, wave function as well...

We analyse the effect of strain on the low temperature electron mobility in a pseudomorphic GaAs/InxGa1-xAs double quantum well structure. We consider ionized impurity scattering, alloy disorder scattering and interface roughness scattering. In a multisubband occupied system, the intersubband interaction has an important role in the calculation of...

We analyse the effect of uniform electric field on the low temperature multisubband electron mobility in an InGaAs/InAlAs double quantum well structure in which the side barriers are delta-doped with layers of Si. The electric field, which is perpendicular to the interface plane of the structure, alters the subband energy levels and wave functions...

We analyze the strain induced changes in the low temperature multisubband electron mobility mediated through the intersubband interactions in a pseudomorphic GaAs/InxGa1−xAs coupled double quantum well structure. We consider the non-phonon scattering mechanisms and study the effect of strain on them. We show that strain reduces the mobility due to...

This paper presents an approach for calculating coupling efficiency in a holey fiber holographic coupler system. There are two main contributions of this work. First, the current work is an attempt to analyze the coupling efficiency between two holey fibers for the first time using a holographic coupler. Second, our numerical analysis provides some...

The effect of uniform electric field on low temperature ( T =0 K ) multisubband electron mobility μ_i is analyzed by considering a barrier delta-doped Ga _0.5 In _0.5 P / GaAs coupled double quantum well structure. We consider ionized impurity scattering and interface roughness (IR) scattering. The screening of the sca...

We analyse the effect of interface roughness scattering on low temperature electron mobility μn mediated by intersubband interactions in a multisubband coupled Ga0.5In0.5P/GaAs quantum well structure. We consider a barrier δ-doped double quantum well system in which the subband electron mobility is limited by the interface roughness scattering μIRn...

We study the effect of bond angle and dihedral angle disorder on the diamagnetic susceptibility (χ) of a model amorphous semiconductor by adopting a linear combination of hybrids formalism. We have constructed orthormal basis states for the disorder network by introducing distortion in bond angles and dihedral angles. We have used the disorder basi...

We analyse the low temperature subband electron mobility in a Ga0.5In0.5P/GaAs quantum well structure where the side barriers are delta-doped with layers of Si. The electrons are transferred from both the sides into the well forming two dimensional electron gas (2DEG). We consider the interface roughness scattering in addition to ionised impurity s...

We study the effects of intersubband coupling and screening on the low temperature electron mobility mu_n in an Al_0.2Ga_0.8As / In_0.2Ga_0.8As / GaAs barrier-delta doped asymmetric quantum well structure by considering the ionized impurity scattering and alloy disorder scattering. We note that the...

In this invited talk, we briefly review the work done on low temperature electron subband mobility μn in various δ-doped systems. We then analyse μn in double quantum well structures, which exhibits the tunneling coupling in addition to confinement effect. We discuss the importance of intersubband coupling on μn in a multisubband system. The effect...

We study low temperature electron transport mobility μ_n in a GaAs / In _x Ga _1-x As double quantum well structure. Both the extreme barriers are δ doped with Si so that the electrons diffuse into the adjacent wells ( InGaAs layers) forming two sheets of two-dimensional electron gas separated by a thin central barrier...

We study low temperature electron mobility μnin a GaAs/Alx Ga 1−xAs coupled double quantum well structure. Both the extreme barriers are δ -doped with Si so that the electrons diffuse into the adjacent wells forming two sheets of two-dimensional electron gas (2DEG) separated by a thin central barrier. The subband electron wavefunctions and energy l...