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Point-of-care (POC) devices have shown a promising response in healthcare and diagnosis due to their accurate response, low cost, portability, and nonrequirement of specialized equipment. These devices have changed the traditional diagnostic platform to new and advanced diagnostic technology. The main objective is to develop a small chip-based, miniaturized device that can be used for the immediate detection of different pathogens. So to carry out detection of analytes having low volumes and with higher sensitivity, POC devices can be made with microfluidic technologies. Microfluidics integrated with biosensor technology allows the detection of small volumes of liquid in a channeled and automated way to improve POC-based diagnostics. Recently, considerable progress has been noticed in the development of miniaturized devices including miniaturized wearable diagnosis devices. So the present chapter summarizes the development, applications of different microfluidic-based miniaturized devices, and their limitations.

In this research work we have coated WC (tungsten carbide) tool inserts with diamond like carbon coatings. The deposition was done using the thermal Chemical Vapour Deposition (CVD) method. We have used bagasse of sugarcane which is an agriculture waste as a carbon precursor for developing the diamond like carbon coatings. Surface finish, cutting temperature and cutting forces of as-developed diamond like carbon coatings on the WC inserts were examined and analyzed in this research work. For confirming the presence of diamond like carbon coatings on the surface of coated tungsten carbide (WC) tool inserts substrate we have used Raman spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (Fe-SEM). The increase in the hardness on the developed coated samples were inspected by performing the hardness test on the coated substrates. The average evaluated Vickers Hardness number were found to be 1455.24 HV and 950.65 HV for both coated as well as un-coated samples respectively. This shows 53% rise in the hardness of the un-coated WC inserts.

In this paper a self-developed polycrystalline diamond coating was done on tungsten carbide (WC) tool insets by using simple thermal chemical vapor deposition technique. The growth of these diamond films has been carried out at ~900 ºC temperature. The as-grown polycrystalline diamond films on the surface of tungsten carbide tool inserts have been characterized using Raman spectrometer and scanning electron microscope (SEM). The morphological studies reveal that the as-grown diamond films are of high crystalline quality. The as-grown diamond films possess compressive stress. The micro-hardness indentation test of the as-grown diamond films on WC tool inserts and bare have also been done and it has been found that the Vicker’s hardness of the as-grown diamond WC tool inserts is found to be 1423.32 HV which is 29% better than the un-coated tools.

Here we demonstrate that by using sugarcane bagasse as a carbon precursor, highly crystalline diamond films possessing H3 [N-V-N] and [Si-V]− optical centers can be grown on Si (100) substrates using a simple thermal chemical vapor deposition (thermal-CVD) system at atmospheric pressure and reduced temperature (~900 °C). In this process, the rich chemistry of effluent gas species produced during the pyrolysis of sugarcane bagasse is found to play a vital role. Diamond films have also been characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), micro-Raman, and photoluminescence (PL) spectrometer. Presence of nitrogen and silicon related defect was probed by PL and H3, i.e. [N-V-N] at 505 nm and [Si-V]− at 736 nm optical centers have been confirmed. The other observed peaks at 445.7 nm, 468 nm, and 884 nm are assigned to nitrogen-containing defects.

The present study aims to demonstrate the application of sugarcane bagasse as an excellent field emitter. Field emission property of as-pyrolyzed sugarcane bagasse (p-SBg) before and after the plasma treatment has been investigated. It has been observed that electronic nature of p-SBg transformed from semiconducting to metallic after plasma treatment. Maximum current and turn-on field defined at 10 μA/cm2 was found to be 800 μA/cm2 and 2.2 V/μm for as-pyrolyzed sugarcane bagasse (p-SBg) and 25 μA/cm2 and 8.4 V/μm for H2-plasma treated p-SBg. These values are found to be better than the reported values for graphene and activated carbon. In this report, pyrolysis of bagasse has been carried in a thermal chemical vapor deposition (Th-CVD) system in inert argon atmosphere. Scanning electron microscopy (SEM), X-ray Diffraction (XRD), High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) have been used to study the structure of both pre and post plasma-treated p-SBg bagasse’s sample. HRTEM study reveals that carbonaceous structures such as 3D-nanographene oxide (3D-NGO), graphite nanodots (GNDs), carbon nanotubes (CNTs), and carbon onions are present in both pre-treated and plasma-treated p-SBg. Hence, we envision that the performed study will be a forwarding step to facilitate the application of p-SBg in display devices.

In this paper, structure of n-type WSe2/p-type Si heterojunction solar cell has been simulated by using AFORS-HET software version 2.5 at AM1.5. In order to get maximum power conversion efficiency (PCE), parameters of both tri-layer tungsten diselenide (WSe2) and Si have been optimized. In the present study, tri-layer WSe₂ has been considered as 3-D in nature instead of the reported 2-D nature. After optimizing the parameters of both tri-layer WSe2 and silicon wafer, PCE of nearly 13.09 % has been achieved which decreases to 8.9 % as number of layers of WSe2 increases from 3 to 40. Furthermore, maximum value PCE has been found to be 6.8 % when parameters of commercial available silicon wafer were taken for simulation. We have also analyzed the effect of temperature as well as the spectral response in order to make the best optimized solar cell. In the present work, we have demonstrated that n-type tri-layered WSe2 has an immense potential to be used as an excellent transparent conducting electrode.

Silica, generally known as silicon dioxide is insulating in nature whereas silicon is semiconducting. These two materials are widely used in sensing and electronic devices. In order to full-fill demand of silicon, sources other than sand, have to explore for silicon extraction. In this report, bamboo culms have been subjected to thermo chemical decomposition at high temperature (1250 °C) in an inert atmosphere. After pyrolysis, contents in residual of bamboo culms have been characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Nanosized, pure crystalline Si has been formed. Si as well as charcoal is found to be crystalline in nature. No silicon carbide formation observed. Copyright © 2016 VBRI Press.

In this report, we have illustrated the synthesis of the Ni-filled multiwalled carbon nanotubes (MWCNTs) on both metallic and non-metallic substrates, by using thermal CVD technique. Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) have been used to characterize the surface morphology and crystalline nature of the MWCNTs encapsulated with Ni nanorod. These filled MWCNTs have exhibited strong magnetic response due to encapsulation of pure phase of Ni. Magnetic Force Microscopy (MFM) study of such filled tubes reveals the pole formation in the Ni nanorod and confirms magnetization direction perpendicular to tube axis. Filling occurs in a fragmented manner confirmed by MFM and each fragment found to have north and south poles along the axis perpendicular to the tube i.e. radial direction of tube. Copyright © 2016 VBRI Press.

Filled or un-filled multiwalled carbon nanotubes (CNTs) used in this study have been synthesized by the floating catalyst method and fixed catalyst method, respectively. The thermal stability of filled/un-filled carbon nanotubes has been investigated by using Thermogravimetric analysis (TGA) and Derivative thermogravimetric (DTG) analysis. In this report, we have developed a methodology to distinguish between filled and un-filled carbon nanotubes. Filled-CNTs are found to be more resistant to oxidation than the un-filled carbon nanotubes. The calculated activation energy of as-grown filled CNTs, by using differential method, determined to be 3.29 ± 0.04 eV, which is higher than that of highly ordered pyrolytic graphite (HOPG). Carboneous impurities; amorphous carbon, catalyst and CNT of different diameter, which are structurally different, are identified by their reactivity and the resistance to oxidation. Copyright © 2016 VBRI Press.

The present study aims to deduce the in-situ response of iron carbide (Fe3C) nanorod filled inside carbon nanotube (CNT) under electron irradiation. Electron irradiation on Fe3C filled-CNT at both high and room temperature (RT) has been performed inside transmission electron microscope. At high temperature (HT), it has been found that γ-Fe atoms in lattice of Fe3C nanorod accumulate first and then form the cluster. These clusters follow the inverse Ostwald ripening whereas if e-irradiation is performed at RT then only the morphological changes in both carbon nanotube as well as nanorod are observed. Compression generated either by electron beam heating or by shrinkage of CNT walls is observed to be a decisive factor.

The present study aims to deduce the confinement effect on the magnetic properties of iron carbide (Fe3C) nanorods filled inside carbon nanotubes (CNTs), and to document any structural phase transitions that can be induced by compressive/tensile stress generated within the nanorod. Enhancement in the magnetic properties of the nanorods is attributed to tensile stress as well as to compression, present in the radial direction and along the nanotube axis, respectively. Finally, the growth of permanent cylindrical nanomagnets has been optimized by applying a field gradient. Besides presenting the growth model of in situ filling, we have also proposed the mechanism of magnetization of the nanotubes. Magnetization along the tube axis has been probed by confirming the pole formation. Fe3C has been selected because of its ease of formation, low TC and incompressibility.

In the present study, we report an effective way for reduction of graphene oxide (GO) as well as tuning of bandgap using various reducing agents. It is found that sodium borohydride (NaBH4) can be a promising reducing agent, as it can reduce the bandgap to 2.30 eV and has a higher capacity to restore the carbon–carbon bonds compared with other reducing agents. Further bandgap tuning has been obtained by hydrogenation of GO as well as NaBH4-reduced GO (NGO). It was observed that after hydrogenation, the bandgap of GO was reduced from 2.48 to 1.95 eV, whereas it reduced from 2.45 to 1.87 eV in NGO. Hydrogenation of GO results in rearranging of C=O functionalities and removal of oxygen-containing groups. Furthermore, transmission electron microscopy observations corroborate the observation that after reduction with NaBH4, GO shows a more uniform nature than GO. The intensity ratio (I{1,100}/I{1,200}) of the {1,200} and {1,100} planes is found to be 1. After reduction with NaBH4, the ID/IG ratio decreased from 1.05 to 0.92, suggesting a decrease in defect density and better reduction. The intrinsic work function of GO and hydrogenated NGO is determined using electrostatic force microscopy and found to be 5.19 ± 0.1 eV and 4.39 ± 0.1 eV, respectively.