Mukul K. Das

Bio: Mukul K. Das is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Quantum well & Solar cell. The author has an hindex of 10, co-authored 76 publications receiving 295 citations. Previous affiliations of Mukul K. Das include Indian Institute of Technology Dhanbad & Narula Institute of Technology.

Theoretical estimation of optical gain in Tin-incorporated group IV alloy based transistor laser

Abstract: We have calculated the electronic band structure and polarization dependent optical gain in a strain balanced SixGeySn1−x−y/GezSn1−z based transistor laser (TL) with GezSn1−z single quantum well (QW) in the base. Design consideration for QW is also addressed to ensure moderate carrier and optical confinement. A significant TE mode optical gain is obtained in mid infra red region for the transition of Г valley conduction band to heavy hole valence band. Optical gain in the QW plays an important role in determining the optical characteristics of Tin (Sn) incorporated group IV material based TL.

Improvement on LEACH Protocol in Wireless Sensor Networks

Abstract: Wireless Sensor Networks (WSNs) have great potential to support several important wireless applications, including real-time multimedia communication, medical applications, surveillance using sensor networks, industrial applications, military surveillance and home networking applications. But there are two challenging issues (i) communication bandwidth and (ii) energy are very important to design wireless and mobile systems because these are very much limited in network environment. Therefore it requires intelligent communication and design techniques to increase bandwidth as well as energy efficient protocol. The most efficient routing protocol LEACH (Lower Energy Adaptive Clustering Hierarchy) in wireless sensor networks (WSNs) has been incorporated by Heinzelman et.al. LEACH uses the concept of dynamic clustering when sensor nodes are deploying randomly where number of cluster impact on the network. This paper describes the network quality that depends on different characteristics of data transmission as a Modification on LEACH protocol. In this paper, we discussed and explain the comparison of magnitude, phase, phase delay, group delay, amplitude of broadcasting and energy consumption respectively.

Low-Energy Adaptive Unequal Clustering Protocol Using Fuzzy c-Means in Wireless Sensor Networks

Abstract: Clustering technique in wireless sensor networks incorporate proper utilization of the limited energy resources of the deployed sensor nodes with the highest residual energy that can be used to gather data and send the information. However, the problem of unbalanced energy consumption exists in a particular cluster node in the network. Some more powerful nodes act as cluster head to control sensor network operation when the network is organized into heterogeneous clusters. It is important to assume that energy consumption of these cluster head nodes is balanced. Often the network is organized into clusters of equal size where cluster head nodes bear unequal loads. Instead in this paper, we proposed a new protocol low-energy adaptive unequal clustering protocol using Fuzzy c-means in wireless sensor networks (LAUCF), an unequal clustering size model for the organization of network based on Fuzzy c-means (FCM) clustering algorithm, which can lead to more uniform energy dissipation among the cluster head nodes, thus increasing network lifetime. A heuristic comparison between our proposed protocol LAUCF and other different energy-aware protocol including low energy adaptive clustering hierarchy (LEACH) has been carried out. Simulation result shows that our proposed heterogeneous clustering approach using FCM protocol is more effective in prolonging the network lifetime compared with LEACH and other protocol for long run.

Theoretical analysis of direct transition in SiGeSn/GeSn strain balanced QWIP

Abstract: This work presents a theoretical analysis of direct transition in strain balanced SiGeSn/GeSn quantum well infrared photodetector. Eigen energies for Г valley conduction band, heavy hole band and light hole band are obtained from the self consistent solution of coupled Schrodinger and Poisson equations by finite difference method. Absorption spectra for direct transition of heavy hole and light hole band to Г valley are calculated after evaluating Eigen energies and wave functions. Significant absorption in infrared region is obtained for heavy hole band–Г valley conduction band transition. A significant shift in absorption peak towards longer wavelengths is observed in presence of electric field considering excitonic effect.

Numerical Methods For Partial Differential Equations

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Tuning the Electro-optical Properties of Germanium Nanowires by Tensile Strain

Abstract: In this Letter we present the electrical and electro-optical characterization of single crystalline germanium nanowires (NWs) under tensile strain conditions. The measurements were performed on vapor–liquid–solid (VLS) grown germanium (Ge) NWs, monolithically integrated into a micromechanical 3-point strain module. Uniaxial stress is applied along the ⟨111⟩ growth direction of individual, 100 nm thick Ge NWs while at the same time performing electrical and optical characterization at room temperature. Compared to bulk germanium, an anomalously high and negative-signed piezoresistive coefficient has been found. Spectrally resolved photocurrent characterization on strained NWs gives experimental evidence on the strain-induced modifications of the band structure. Particularly we are revealing a rapid decrease in resistivity and a red-shift in photocurrent spectra under high strain conditions. For a tensile strain of 1.8%, resistivity decreased by a factor of 30, and the photocurrent spectra shifted by 88 meV...

Secure communication in wireless sensor networks based on chaos synchronization using adaptive sliding mode control

Abstract: Due to resource constraints in wireless sensor networks and the presence of unwanted conditions in communication systems and transmission channels, the suggestion of a robust method which provides battery lifetime increment and relative security is of vital importance. This paper considers the secure communication in wireless sensor networks based on new robust adaptive finite time chaos synchronization approach in the presence of noise and uncertainty. For this purpose, the modified Chua oscillators are added to the base station and sensor nodes to generate the chaotic signals. Chaotic signals are impregnated with the noise and uncertainty. At first, we apply the modified independent component analysis to separate the noise from the chaotic signals. Then, using the adaptive finite-time sliding mode controller, a control law and an adaptive parameter-tuning method is proposed to achieve the finite-time chaos synchronization under the noisy conditions and parametric uncertainties. Synchronization between the base station and each of the sensor nodes is realized by multiplying a selection matrix by the specified chaotic signal which is broadcasted by the base station to the sensor nodes. Simulation results are presented to show the effectiveness and applicability of the proposed technique.

State of the Art and Future Perspectives in Advanced CMOS Technology.

Abstract: The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today's transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore's law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.