Najeeb-ud-din Hakim

@nitsri.ac.in

Professor, Electronics and Communication Engineering
National Institute of Technology Srinagar



        

https://researchid.co/najeebuddin

RESEARCH, TEACHING, or OTHER INTERESTS

Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials

66

Scopus Publications

Scopus Publications

  • Deconvoluting the transport mechanisms using electrical impedance spectroscopy in heterojunction organic solar cells doped with trimetallic nanospheres
    Baseerat Khan and Hakim Najeeb-ud-din
    IOP Publishing
    Abstract Nano-plasmonic structures have attracted the interest of researchers owing to their advantageous properties in solar cells. Ternary nanospheres lead to better charge conduction pathways, thereby reducing losses and boosting efficiency. The synergistic plasmonic effects of the tri-metallic nanospheres enable broader spectral absorption, making them superior for enhancing solar cell performance. This paper presents the simulation study of transportation mechanism and carrier kinetics in poly(3-hexylthiophene): [6,6]-phenyl-butyric acid methyl ester [P3HT: PCBM]-based organic solar cell doped with ternary nanospheres of silver, gold, and copper, which has not been explored prior. Critical electrical parameters, such as relaxation time, charge carrier mobility, diffusion time, flat-band voltage, and doping density, have been determined through AC analysis of the device. SETFOS, an instrumental one-dimensional tool, is used to determine these parameters using methods like impedance spectroscopy, Mott–Schottky analysis and Capacitance–Voltage modelling. This extensive examination allows for a better understanding of the device’s behaviour in the presence of ternary nanospheres. The tri-metallic nanoparticle-doped organic solar cells provide better performance parameters compared with the performance of an undoped solar cell. Further, circuit modelling of solar cells is done to facilitate the optimisation by allowing the simulation and prediction of performance parameters under various operating conditions.

  • Modeling and design of non-fullerene organic solar cells using pyramidal lens arrays
    Asma Iqbal Wani, Farkhanda Ana, and Najeeb-Ud-Din Hakim
    Elsevier BV

  • Study on structure and thermal stability properties of cellulose fibers derived from Nelumbo nucifera rhizome
    Mehvish Shah and Najeeb ud din Hakim
    Springer Science and Business Media LLC


  • Analytical modeling of contact resistance and recombination for silicon heterojunction solar cells using hybrid carrier selective passivating contacts
    Bisma Bilal and Hakim Najeeb-ud-Din
    IOP Publishing
    Abstract Silicon heterojunction solar cells using Carrier Selective Passivating Contacts (CSPC) are the potential contenders for high efficiency next generation photovoltaics. Besides numerical simulations, the mathematical analysis of parameters affecting the performance of these cells is gaining considerable attention. In this work, the factors affecting the selectivity of silicon heterojunction solar cell using Hybrid Carrier Selective Passivating Contacts (H-CSPC) are investigated. This includes the evaluation of contact resistance and recombinations in the device. The contact resistance is analyzed in terms of partial resistances wherein an equivalent resistance model for the cell using H-CSPC is devised and resistances are inspected using quasi fermi level collapse over the contacts. The selectivity of the cell at each contact is examined and the condition for maximum selectivity is derived. Further, the recombinations in different regions of the cell using H-CSPC are analyzed. The recombinations at the TiO2/c-Silicon interface strongly deteriorate the V oc of the cell which is quantified using an analytical model under interface defect constraints and the results obtained are compared with simulations.



  • Computational Analysis of Antireflection Coatings for Semiconductor Solar Cells
    Bisma Bilal and Hakim Najeeb-ud-Din
    Springer Nature Singapore


  • Analog-to-digital converters: a review of existing architectures and a new proposal for high resolution sensors
    Saima Bashir, Najeeb-ud-din Hakim, and G.M. Rather
    Emerald
    Purpose As technology advances the demand for an analog-to digital converter has increased, as every application demands a converter as per its parameters. Currently, work is done on improvement of data converters at three levels of design – architectural, circuit and physical level. This paper aims to review the work done in the field of analog-to-digital converters (ADCs) at architectural and circuit level and discusses the achievements in this field. Furthermore, a new architecture is proposed, which works at higher resolution and provides optimum design parameters at low power consumption. Design/methodology/approach A hybrid architecture combining the features of synthetic approximation register and sigma-delta ADC is presented. The validity of the proposed design at architectural level is verified using MATLAB SIMULINK simulations. Findings The design simulation was tested for a sinusoidal wave of 1 V at the test frequency of 60 Hz. The design consumes least power, and is found to yield an error of the order less than 10–3 V, thus providing highly accurate digital output. Originality/value The design is applicable in many applications including biomedical systems, Internet-of-Things and earthquake engineering. This architecture can be further optimized to obtain better performance parameters.


  • Comprehensive field pattern analysis for tailoring of reflectance in a hybrid subwavelength plasmonic grating refractive index sensor and its potential for noninvasive salivary glucose monitoring
    Taban Qayoom and Hakim Najeeb-ud-din
    Optica Publishing Group
    A compact hybrid two-dimensional plasmonic subwavelength grating composed of gold and semiconductor ZnS is proposed. By implementing the finite-difference time-domain numerical technique, detailed field pattern analysis and reflectance characteristics of the grating structure are comprehensively investigated, tailored, and improved. An unfamiliar phenomenon of exponential decrease in resonance wavelength with an increase in groove width is observed, validated, and empirically modeled. This confirms that the reflectance resonance dip is because of the surface plasmon resonance in the grating structure, unlike the resonance dip obtained in the diffraction grating because of the Fabry–Perot resonance. A rigorous sensitivity analysis is performed for both generalized bulk and surface analyte detection. The surface sensitivity is observed to be 100.5 nm/RIU at dip 1 for 10-nm-surface analyte thickness. The bulk sensitivity for dip 1 and dip 2 was 104.3 nm/RIU and 800 nm/RIU, respectively. The refractive index range variation of dip 1 for the surface analyte is correlated with the refractive index of the blood by using the linear refractive index model and Gladstone–Dale law for blood. A linear regression analysis correlating blood glucose and salivary glucose with a surface analyte is used. The proposed sensor is observed to be promising for noninvasive salivary glucose monitoring with high surface sensitivity of 1.104 nm/mg/dl with a compact footprint of about 0.5 µ m × 0.2 µ m in x − z dimensions.


  • Adaptive hybrid arbiter design for real-time traffic-aware scheduling
    Afshan Amin Khan, Roohie Naaz Mir, and Najeeb-Ud Din
    Emerald
    Purpose This work focused on a basic building block of an allocation unit that carries out the critical job of deciding between the conflicting requests, i.e. an arbiter unit. The purpose of this work is to implement an improved hybrid arbiter while harnessing the basic advantages of a matrix arbiter. Design/methodology/approach The basic approach of the design methodology involves the extraction of traffic information from buffer signals of each port. As the traffic arrives in the buffer of respective ports, information from these buffers acts as a source of differentiation between the ports receiving low traffic rates and ports receiving high traffic rates. A logic circuit is devised that enables an arbiter to dynamically assign priorities to different ports based on the information from buffers. For implementation and verification of the proposed design, a two-stage approach was used. Stage I comprises comparing the proposed arbiter with other arbiters in the literature using Vivado integrated design environment platform. Stage II demonstrates the implementation of the proposed design in Cadence design environment for application-specific integrated chip level implementation. By using such a strategy, this study aims to have a special focus on the feasibility of the design for very large-scale integration implementation. Findings According to the simulation results, the proposed hybrid arbiter maintains the advantage of a basic matrix arbiter and also possesses the additional feature of fault-tolerant traffic awareness. These features for a hybrid arbiter are achieved with a 19% increase in throughput, a 1.5% decrease in delay and a 19% area increase in comparison to a conventional matrix arbiter. Originality/value This paper proposes a traffic-aware mechanism that increases the throughput of an arbiter unit with some area trade-off. The key feature of this hybrid arbiter is that it can assign priorities to the requesting ports based upon the real-time traffic requirements of each port. As a result of this, the arbiter is dynamically able to make arbitration decisions. Now because buffer information is valuable in winning the priority, the presence of a fault-tolerant policy ensures that none of the priority is assigned falsely to a requesting port. By this, wastage of arbitration cycles is avoided and an increase in throughput is also achieved.

  • Prime turn model and first last turn model: An adaptive deadlock free routing for network-on-chips
    Misbah Manzoor, Roohie Naaz Mir, and Najeeb-ud-din Hakim
    Elsevier BV



  • Analytical Modeling of the Effect of Silver Nanoparticle Incorporation in Active Layer of an Organic Solar Cell
    Sakshi Koul and Najeeb-ud-din Hakim
    Institute of Electrical and Electronics Engineers (IEEE)
    The incomplete absorption of the incoming light radiation in the absorber layer of the organic solar cell (OSC) is a major issue in OSC technology. Persistent research is being carried out to address this issue and the incorporation of metallic nanoparticles (MNPs) has been considered a viable option. The presence of MNPs in the active layer of the cell enhances the absorption of light, thereby leading to increased cell efficiencies. An effort has been made to critically evaluate the incorporation of spherical silver nanoparticles in the active layer of a Poly (3-hexylthiophene): phenyl-C61-butyric acid methyl ester (P3HT:PCBM) based OSC. The optical properties of the active layer are affected by the incorporated MNPs. The MNPs with their characteristic absorption and scattering cross section affect the absorption capabilities of the active layer absorber material. The absorption coefficient of the active layer also gets modified because of the presence of the MNPs in it. An analytical model is proposed to describe the effect of the changing sizes of the incorporated MNPs on the absorption coefficient and the ensuing generation of charge carriers in the OSC. The generation to recombination rate ratio (G/R) has been coined as a performance parameter for the quantification of the effect of the introduction of MNPs in OSCs. This parameter has not been used earlier for the performance analysis of the MNP-incorporated OSCs.

  • Fundamentals of and Recent Advances in Carrier Selective Passivating Contacts for Silicon Solar Cells
    Bisma Bilal and Hakim Najeeb-ud-Din
    Springer Science and Business Media LLC



  • A REVIEW OF DESIGN APPROACHES FOR ENHANCING THE PERFORMANCE OF NOCS AT COMMUNICATION CENTRIC LEVEL
    Misbah Manzoor, Roohie Naaz Mir, and Najeeb-ud-Din Hakim
    Scalable Computing: Practice and Experience
    As the trend of technology shrinking continues a vast amount of processors are being incorporated in a limited space. Due to this almost half of the chip area in Multi-Processor Systems-on-Chips (MPSoCs) is under interconnections, which pose a big problem for communication. Network-on-Chips (NoCs) evolved as a significant scalable solution for removing wiring congestion and communication problem in MPSoCs. NoCs provide the advantage of customized architecture, increased scalability and bandwidth. NoC is a structured framework where communication is the prime concern. In this review paper we present an overview of research and design approaches in the communication centric areas of NoCs. Here we have tried to discuss and iterate most of the available work done for communication in 2D NoCs. This paper gives the insight of different attributes and performance parameters of NoCs. Further it gives a detailed description of how topology, flow control and routing mechanisms can affect the qualitative aspects (performance) of NoCs. It then explains how various attributes of routing can help in increasing the efficacy of NoCs. Subsequently a brief review of different simulators used for NoCs is given. All of this is provided based on the survey of academic, theoretical and experimental approaches presented in the past. Finally some suggestions for future work are also given.


  • Design, characterization and performance evaluation of few-mode EDFA system with propagation up to six modes
    Taban Qayoom, Gausia Qazi, and Hakim Najeeb-ud-din
    Springer Science and Business Media LLC

  • A simple analytical model for the resonant tunneling diode based on the transmission peak and scattering effect
    Sneh Lata Yadav and Hakim Najeeb-ud-din
    Springer Science and Business Media LLC