arXiv subjects

M. M. Uddin

Publications and source records attributed to M. M. Uddin.

41 records · Page 3Linked to original sources

arXiv2016

Design and Performance Analysis of Depletion-Mode InSb Quantum-Well Field-Effect Transistor for Logic Applications

The design of a 1 micrometer gate length depletion-mode InSb quantum-well field-effect transistor (QWFET) with a 10 nm-thick Al2O3 gate dielectric has been optimized using a quantum corrected self-consistent Schrodinger-Poisson (QCSP) and two dimensional drift-diffusion model. The model predicts a very high electron mobility of 4.42 m2V-1s-1 at Vg= 0V, a small pinch off gate voltage (Vp) of -0.25V, a maximum extrinsic transconductance (gm) of 4.94 S/mm and a drain current density of more than 6.04 A/mm. A short-circuit current-gain cut-off frequency (fT) of 374 GHz and a maximum oscillation frequency (fmax) of 645 GHz are predicted for the device. These characteristics make the device a potential candidate for low power, high-speed logic electronic device applications.

cond-mat.mes-hall↗

arXiv2016

Effect of Sintering Temperature on Structural and Magnetic Properties of Ni0.6Zn0.4Fe2O4 Ferrite: Synthesized from Nanocrystalline Powders

The effect of sintering temperatures (Ts) on the structural and magnetic properties of Ni0.6Zn0.4Fe2O4 (NZFO) ferrites synthesized by conventional double sintering method has been reported. The samples are sintered at 1200, 1250 and 1300 °C. The X-ray diffraction (XRD) analysis reveals the formation of a single phase cubic spinel structure of the sample. The magnetic parameters such as saturation magnetization, Ms; coercive field, Hc; remanent magnetization, Mr and Bohr magneton, μB are determined and well compared with reported values. The obtained values are found to be 71.94 emu/gm and 1.2 Oe for Ms and Hc, respectively at Ts=1300 oC. Curie temperature (Tc) at various Ts has also been calculated. It is noteworthy to note that the sample with a very low Hc could be used in transformer core and inductor applications.

cond-mat.mtrl-sci↗

arXiv2015

Structural Properties, Impedance Spectroscopy and Dielectric Spin Relaxation of Ni-Zn Ferrite Synthesized by Double Sintering Technique

Structural properties, impedance, dielectric and electric modulus spectra have been used to investigate the sintering temperature (Ts) effect on the single phase cubic spinel Ni0.6Zn0.4Fe2O4 (NZFO) ceramics synthesized by standard ceramic technique. Enhancement of dielectric constants is observed with increasing Ts. The collective contribution of n-type and p-type carriers yields a clear peak in notable unusual dielectric behavior is successfully explained by the Rezlescu model. The non-Debye type long range dielectric relaxation phenomena is explained by electric modulus formalism. Fast response of the grain boundaries of the sample sintered at lower Ts sample leading to small dielectric spin relaxation time, t (several nanoseconds) have been determined using electric modulus spectra for the samples sintered at different Ts. Two clear semicircles in impedance Cole-Cole plot have also been successfully explained by employing two parallel RC equivalent circuits in series configuration taking into account no electrode contribution. Such a long relaxation time in NZFO ceramics could suitably be used in nanoscale spintronic devices.

cond-mat.mtrl-sci↗

arXiv2013

Gate depletion of an InSb two-dimensional electron gas

We investigated the gate control of a two-dimensional electron gas (2DEG) confined to InSb quantum wells with an Al2O3 gate dielectric formed by atomic layer deposition on a surface layer of Al0.1In0.9Sb or InSb. The wider bandgap of Al0.1In0.9Sb compared to InSb resulted in a linear, sharp, and non-hysteretic response of the 2DEG density to gate bias in the structure with an Al0.1In0.9Sb surface layer. In contrast, a nonlinear, slow, and hysteretic (nonvolatile-memory-like) response was observed in the structure with an InSb surface layer. The 2DEG with the Al0.1In0.9Sb surface layer was completely depleted by application of a small gate voltage (-0.9 V).

cond-mat.mes-hall↗

arXiv2012

Characterization of InSb quantum wells with atomic layer deposited gate dielectrics

We report magnetotransport measurements of a gated InSb quantum well (QW) with high quality Al2O3 dielectrics (40 nm thick) grown by atomic layer deposition. The magnetoresistance data demonstrate a parallel conduction channel in the sample at zero gate voltage (Vg). A good interface between Al2O3 and the top InSb layer ensures that the parallel channel is depleted at negative Vg and the density of two-dimensional electrons in the QW is tuned by Vg with a large ratio of 6.5x1014 m-2V-1 but saturates at large negative Vg. These findings are closely related to layer structures of the QW as suggested by self-consistent Schrodinger-Poisson simulation and two-carrier model.

cond-mat.mes-hall↗