Department of Electrical and Electronics Engineering

Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1925

Browse

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Plasmonic Au Nanoparticles Coated on ReS2 Nanosheets for Visible-Near-Infrared Photodetectors
    (ACS, 2022-07) Hazra, Arnab
    Even though there are various reports on the fabrication of flexible photodetectors, still there is a need for the development of high-performance photodetectors. In recent years, the plasmonic photodetection technique has emerged as one of the prominent solutions to enhance photodetection performance. In this work, a flexible and high-performance broadband (visible-near-infrared (NIR)) plasmonic photodetector is demonstrated by integrating gold (Au) nanoparticles (NPs) on two-dimensional (2D) ReS2 nanosheets. Fabricated Au-NPs/ReS2 showed an approximately 15-fold enhancement in the photodetection performance compared to pristine ReS2. Photoresponsivity of the fabricated Au-NPs/ReS2 device in visible (Vis) and NIR regions is ∼2.1 and ∼1.3 A W–1, respectively. Significant enhancement in the photosensing performance of the device could be a combined effect of multiple factors, including localized surface plasmon resonance and effective charge transfer at the interface of Au-NPs and ReS2. The response speed of the fabricated device is approximately 200 ms. Furthermore, theoretical understanding of light interaction with Au-NPs is studied, and also electromagnetic simulations are performed using Lumerical Finite Difference Time Domain Multiphysics simulation to investigate the plasmon coupling effect of Au-NPs on 2D ReS2 nanosheets. To further understand the photodetection mechanism, the energy band diagram of the Au-NPs/ReS2 interface is drawn using ultraviolet photoelectron spectroscopy measurements.
  • No Thumbnail Available
    Item
    Two dimensional material based sensor for health care applications
    (CRC Press, 2025) Hazra, Arnab
    Following the discovery of graphene, there has been extensive research on 2D materials, leading to a wide range of applications in the healthcare industry due to their unique properties, such as a high surface-to-volume ratio, nanometre-size layered structure, and bandgap tuning capabilities. In this chapter, we have categorized 2D material-based health sensors into three types: (i) Flexible sensors, (ii) Chemical sensors and (iii) Biosensors. Flexible sensors involve stretching or compressing 2D materials on flexible substrates to vary their resistance or capacitance, enabling the detection of body movements and heart rate. The deposition of mono or a few layers of 2D materials on thin, flexible substrates allows for conformal contact-like properties, facilitating proper and easy placement on the skin of the human body. Chemical sensors produce measurable electric signals when a molecule sits on its active layer. Using 2D material as the active layer enhances their sensitivity due to their thin nature and high surface-to-volume ratio. In biosensors, 2D materials are not used for directly sensing biomolecules due to incompatibility with inorganic molecules. Instead, bioreceptor layers are utilized on 2D material to detect the presence of biomolecules. The presence of 2D material provides a planar conducting channel for current transport in biosensors. The sensors discussed in this chapter primarily have field effect transistor device structures and exhibit responses in terms of current and resistance for monitoring human health indicators such as heart rate, glucose level, pH level and early detection of life-threatening diseases such as tuberculosis, cancer and more. This chapter delves into the applications, reliability, scalability, challenges and future applications of 2D materials such as graphene, transition metal dichalcogenides (TMDCs), MXenes and black phosphorus in healthcare systems.