Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Author: search.filters.author.Goel, V.

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Hydroxyapatite—a promising sunscreen filter
    (Springer, 2020) Pal, A.; Hadagalli, K.; Bhat, P.; Goel, V.; Mandal, S.
    Exposure to ultraviolet (UV) radiation has been known to cause skin cancer, erythema, and sunburn. Continuous efforts have been made to make sunscreens more efficient and non-toxic. Inorganic sunscreens like TiO2 and ZnO are continued to be used for a few decades, and they are efficient in giving protection against harmful UV radiation, but they are photochemically active as well. They generate free radicals upon irradiation, which leads to reactive oxygen species (ROS) generation which is harmful to the human skin. Hydroxyapatite (HA) is a biocompatible material as it has a composition the same as the mineral content of the human bone; therefore, it is suitable for the dermatological application. Though HA itself does not provide protection against UV, studies on doped HA with various ions showed excellent performance. Pure HA absorbs only between 200 and 340 nm, with an intense band below 247 nm. HA doped with bivalent Zn2+, Fe2+, and trivalent Fe3+ and Cr3+, showed absorbance in the entire UV region. TiO2 provides absorbance in the entire UV range, while ZnO does so only in UVA. Compared to HA (refractive index, n = 1.6), TiO2 (n = 2.6) and ZnO (n = 1.9) have higher refractive index, which gives unwanted whitening effect. Additional properties can be brought in HA composites by adding material while retaining their individual properties. As HA is not photocatalytic, it does not lead to a generation of free radicals. This paper throws light on several aspects of HA-based sunscreen filters as an emerging future cosmetic material, and brief analysis and conclusions. © 2019, Australian Ceramic Society.
  • No Thumbnail Available
    Item
    Analytical insights into threshold voltage behaviour of vertical linearly doped fully depleted silicon-on-insulator MOSFETs
    (Institute of Physics, 2025) Sharma, S.; Goel, V.; Rawat, G.
    This paper presents a novel two-dimensional (2D) analytical model for the surface potential of a vertical linearly doped (VLD) fully depleted silicon-on-insulator (FDSOI) FET. Moreover, the channel electric field and threshold roll-off are modeled using the surface potential equations. The evanescent-mode analysis method has been employed to determine the channel potential, and ATLAS TCAD is utilised to simulate the subthreshold I–V characteristics of the device. The performance of the proposed device has been compared with the calibrated FDSOI FET. The proposed device demonstrates remarkable improvements over conventional FDSOI FETs: off-state leakage current plunges from 100 nA to 12 pA, while subthreshold swing sharpens from 110 mV dec?1 to 85 mV dec?1, yielding an exceptional ON-to-OFF current ratio enhancement from 7.2 × 103 to 2.8 × 107. The linearly doped channel in the proposed device is developed using the hetero epitaxy method. The proposed device can be used in integrated circuits (ICs) for low-power applications such as laptops and mobile phones. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.