Structural, Optical and Electrical Properties of Undoped and Doped ZnO Thin Films

ZnO, which has high electrochemical stability, wide band gap energy, large excitonic binding energy, intense near band excitonic emission and is non-toxic, have potential applications in all fields. This chapter reviews the structural, optical and electrical properties of undoped and doped ZnO thin films. The type of doping highly influences the structural properties such as grain size, texture coefficient and unit cell properties. The dopants of transition metal and nonmetals have unique characteristics. Moreover, mono-doping and co-doping encourage this research. The optical properties such as bandgap, charge carrier concentrations and transmissions of the films depend on the doping as well as the preparation condition of the films. The effect of doping on its properties is also discussed

Electrochemical Biosensors for Point of care Applications

Biosensor refers to powerful and innovative analytical tool involving biological sensing element and transducer with broad range of applications, such as diagnosis, drug discovery, biomedicine, food safety and processing, environmental monitoring, security and defense. Recent advances in the field of biotechnology, microelectronics, and nanotechnology have improved the development of biosensors. Glucometers utilizing the electrochemical determination of oxygen or hydrogen peroxide employing immobilised glucose oxidase electrode seeded the discovery and development of biosensors. Molecular recognition based on geometry and forces of interaction play an important role in the biosensor development. The advent of nanotechnology led to highly efficient and sensitive biosensors. They also provide an effective immobilisation matrix for the various bioreceptors. Enzymatic and their mimetic (metalloporphyrin)-based biosensors for reactive oxygen, nitrogen species and cytochrome c will also be discussed. The role of antibodies and their applications in immunosensors development for cytochrome c and superoxide dismutase will be highlighted. The electrochemical biosensors are less expensive, miniaturised and used for point-of-care applications. Further, the fabrication of labVIEW based virtual biosensor instrumentation and microcontroller based portable biosensor for wide variety of applications also devices will be presented

Exactly Solvable Problems in Quantum Mechanics

Some of the problems in quantum mechanics can be exactly solved without any approximation. Some of the exactly solvable problems are discussed in this chapter. Broadly there are two main approaches to solve such problems. They are (i) based on the solution of the Schrödinger equation and (ii) based on operators. The normalized eigen function, eigen values, and the physical significance of some of the selected problems are discussed

Structural, Morphological and Optical Properties of Perfume Atomizer Spray Pyrolysis CdO Thin Films: Effect of Solution Volume

CdO films have been deposited on glass substrates with different solution volume (30, 40 and 50 mL) at 200°C using perfume atomizers spray pyrolysis method. X-ray diffraction studies shows that the prepared thin film had cubic and polycrystalline nature. Scanning electron microscope shows the influence of solution volume on surface morphology of the CdO thin film. Optical studies show that in these films the electronic transition is of the direct transition type. The optical energy gap for the films of as deposited are vary from 2.12 to 2.00 eV with solution volume. Photoluminescence results analysis confirmed that the dependence of optical energy gap on solution volume. The Hall measurements were carried out and the results were discussed

Re-Melting Characteristics of a Stellite21 Deposited Part by Direct Energy Deposition Process Using a Pulsed Plasma Electron Beam with a Large Irradiation Area

Several re-melting type post-processing technologies were developed to improve surface qualities and properties of the fabricated part by a metal additive manufacturing process. The aim of this paper is to investigate re-melting characteristics of the Stellite21 deposited part using a pulsed plasma electron beam with a large irradiation area for the improvement of surface characteristics and material usage ratio of the deposited part by a direct energy deposition (DED) process. The influence of process parameters, including acceleration voltage and the number of beam irradiations, on the roughness, the hardness, the thickness, and the morphology of the re-melted region is examined using results of re-melting experiments. Using the experimental results, a novel post-processing method, including a mechanical subtractive process and a re-melting process using a pulsed plasma electron beam, is proposed. The results of post-processing experiments confirm that the proposed method can significantly improve the surface characteristics and the material usage ratio of the DED par