Deepak Kumar Jarwal

Bio: Deepak Kumar Jarwal is an academic researcher from Indian Institute of Technology (BHU) Varanasi. The author has contributed to research in topics: Scanning electron microscope & Solar cell. The author has an hindex of 8, co-authored 22 publications receiving 173 citations.

CuO Nanowire-Based Extended-Gate Field-Effect-Transistor (FET) for pH Sensing and Enzyme-Free/Receptor-Free Glucose Sensing Applications

Abstract: In this work, multifunctional CuO nanowires (NWs) electrode-based extended-gate (EG) field-effect transistor (FET) has been explored for both pH and glucose sensing applications. The CuO nanowires (NWs) electrode-based EGFET gives good pH sensitivity (~48.34 mV/pH), high linearity (99.84%), good stability for pH level in between 2 and 12 for 12 hours with a drift rate of 2.5mV/h, and good reversibility in terms of low hysteresis loss of 2.5mV. The selectivity of this pH sensor towards hydrogen ion is significantly higher as compared to Na+, K+, Zn++ and Mg++ ions. In addition to the pH sensing, CuO NWs based electrode-based EGFET has also been explored for glucose-sensing for the first time without taking the help of neither any enzyme nor any organic receptor. The proposed glucose sensor gives a good sensitivity of 3.03 mV/mM with a high range of linearity (1mM-12mM), which covers up the glucose level of human blood ranging from 3.6 mM to 6.6 mM. This novel concept of CuO NWs based EG-FET glucose sensing is believed to be extended for sensing other saccharides such as fructose, sucrose, and mannose.

Superficial fabrication of gold nanoparticles modified CuO nanowires electrode for non-enzymatic glucose detection

Abstract: This paper describes a low-cost facile method to construct gold (Au) nanoparticles (NPs) modified copper oxide (CuO) nanowires (NWs) electrode on copper foil for the detection of glucose. Copper foil has been converted to aligned CuO NWs arrays by sequential formation of Cu(OH)2 followed by heat treatment induced phase transformation to CuO. Au NPs are deposited on CuO NWs via simple reductive solution chemistry to impart high surface to volume ratio and enhanced catalytic activity of the resulting electrode. Structure, microstructure and morphology of Cu, Cu(OH)2 NWs, CuO NWs, and Au NPs modified CuO NWs are investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The homogeneous distribution of Au NPs (average diameter ∼12 nm) on CuO NWs (average diameter 100 nm and aspect ratio ∼20) is confirmed by high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) and elemental mapping. This CuO based glucose detection method gives the highest sensitivity along with the maximum linearity range. This non-enzymatic glucose sensor based on Au modified CuO NWs electrode gives broad linearity range from 0.5 μM to 5.9 mM. The sensor exhibits sensitivity of 4398.8 μA mM−1 cm−2, lower detection limit of 0.5 μM, and very fast response time of ∼5 s. Properties of the proposed glucose sensor are also investigated in human blood and it is found that the sensor is highly accurate and reliable. In addition, higher sensitivity and lower detection limit confirm that this device is suitable for invasive detection in saliva and urine.

Fibrous Al-Doped ZnO Thin Film Ultraviolet Photodetectors With Improved Responsivity and Speed

Abstract: Ultraviolet (UV) detection properties of undoped ZnO and Al-doped ZnO (AZO) based interdigitated metal-semiconductor-metal (MSM) structure are investigated in this paper. High quality of fibrous Al-doped ZnO thin films with enhanced conductivity and optical response with controlled doping of Al are synthesized using low-cost sol-gel method. The surface morphology and absorption properties of the films have been investigated. The responsivity and detectivity characteristics of both the devices are compared over 300–700 nm wavelengths. The Al-doped ZnO based Ag/AZO/Ag MSM structure show the maximum responsivity and detectivity of ~5.63 A/W and $\sim 1.8\times 10 ^{12}$ cmHz1/2W−1 while the respective values for the Ag/undoped-ZnO/Ag photodetector are ~3.65 A/W and $\sim 1.3\times 10 ^{12}$ cmHz1/2W−1 at 365 nm and $34~\mu \text{W}$ /cm2 incident UV intensity. The proposed AZO based MSM photodetector has smaller rise time (~30 s) than that (~35 s) of the undoped ZnO based MSM photodetector. However, the AZO based device shows slightly poor spectrum selectivity over the undoped ZnO based device.

Au nanoparticles modified CuO nanowireelectrode based non-enzymatic glucose detection with improved linearity.

Abstract: This paper explores gold nanoparticle (GNP) modified copper oxide nanowires(CuO NWs)based electrode grown on copper foil for non-enzymatic glucose detection in a wide linear ranging up to 31.06 mM, and 44.36 mM at 0.5 M NaOH and 1 M NaOH concentrations. The proposed electrode can be used to detect a very low glucose concentration of 0.3 µM with a high linearity range of 44.36mM and sensitivity of 1591.44 µA mM−1 cm−2. The electrode is fabricated by first synthesizing Cu (OH)2 NWs on a copper foil by chemical etching method and then heat treatment is performed to convert Cu (OH)2 NWs into CuO NWs. The GNPs are deposited on CuO NWs to enhance the effective surface-to-volume ratio of the electrode with improved catalytic activity. The surface morphology has been investigated by XRD, XPS, FE-SEM and HR-TEM analysis. The proposed sensor is expected to detect low-level of glucose in urine, and saliva. At the same time, it can also be used to measure extremely high sugar levels (i.e. hyperglycemia) of ~ 806.5454 mg/dl. The proposed sensor is also capable of detecting glucose after multiple bending of the GNP modified CuO NWs electrode. The proposed device is also used to detect the blood sugar level in human being and it is found that this sensor’s result is highly accurate and reliable.

Fabrication and characterization of a ZnO quantum dots-based metal-semiconductor-metal sensor for hydrogen gas.

Abstract: This paper reports an interdigitated metal-semiconductor-metal (MSM) based hydrogen gas (H2) sensor using colloidal zinc oxide (ZnO) quantum dots (QDs) as the sensing material. The active layer is obtained by spin coating of as-synthesized colloidal ZnO QDs on a SiO2/Si substrate in which the SiO2 layer is grown by oxidation of the Si substrate. The surface morphology of a ZnO QDs -based active film is measured using scanning electron microscopy (SEM) and atomic force microscopy (AFM) support for enhanced gas response. The change in current is measured for different concentrations of H2 gas at 175 °C in an ambient air atmosphere. Reasonably good gas responses of ∼41% for 1% H2 gas and 83.2% for 4% H2 gas have been obtained in ambient air condition. A high selectivity of the proposed sensor with respect to ammonia, sulfur dioxide and organic vapours such as acetone, methanol, chlorobenzene, and chloroform has also been achieved due to nanostructure ZnO films.

The Design of CMOS Radio-Frequency Integrated Circuits: RF CIRCUITS THROUGH THE AGES

Abstract: This expanded and thoroughly revised edition of Thomas H. Lee's acclaimed guide to the design of gigahertz RF integrated circuits features a completely new chapter on the principles of wireless systems. The chapters on low-noise amplifiers, oscillators and phase noise have been significantly expanded as well. The chapter on architectures now contains several examples of complete chip designs that bring together all the various theoretical and practical elements involved in producing a prototype chip. First Edition Hb (1998): 0-521-63061-4 First Edition Pb (1998); 0-521-63922-0

A Critical Review of Electrochemical Glucose Sensing: Evolution of Biosensor Platforms Based on Advanced Nanosystems.

Abstract: The research field of glucose biosensing has shown remarkable growth and development since the first reported enzyme electrode in 1962. Extensive research on various immobilization methods and the improvement of electron transfer efficiency between the enzyme and the electrode have led to the development of various sensing platforms that have been constantly evolving with the invention of advanced nanostructures and their nano-composites. Examples of such nanomaterials or composites include gold nanoparticles, carbon nanotubes, carbon/graphene quantum dots and chitosan hydrogel composites, all of which have been exploited due to their contributions as components of a biosensor either for improving the immobilization process or for their electrocatalytic activity towards glucose. This review aims to summarize the evolution of the biosensing aspect of these glucose sensors in terms of the various generations and recent trends based on the use of applied nanostructures for glucose detection in the presence and absence of the enzyme. We describe the history of these biosensors based on commercialized systems, improvements in the understanding of the surface science for enhanced electron transfer, the various sensing platforms developed in the presence of the nanomaterials and their performances.