Studies on Hall Effect and DC Conductivity Measurements of Semiconductor Thin films Prepared by Chemical Bath Deposition (CBD) method

Semiconductors have various useful properties that can be exploited for the realization of a large number of high performance devices in fields such as electronics and optoelectronics. Many novel semiconductors, especially in the form of thin films, are continually being developed. Thin films have drawn the attention of many researchers because of their numerous applications. As the film becomes thinner, the properties acquire greater importance in the miniaturization of elements such as resistors, transistors, capacitors, and solar cells. In the present work, copper selenide (CuSe), cadmium selenide (CdSe), zinc selenide (ZnSe), lead sulphide (PbS), zinc sulphide (ZnS), and cadmium sulphide (CdS) thin films were prepared by chemical bath deposition (CBD) method. The prepared thin films were analyzed by using Hall measurements in Van Der Pauw configuration (ECOPIA HMS-3000) at room temperature. The Hall parameters such as Hall mobility of the material, resistivity, carrier concentration, Hall coefficient and conductivity were determined. The DC electrical conductivity measurements were also carried out for the thin films using the conventional two – probe technique. The activation energies were also calculated from DC conductivity studies

Studies on Hall Effect and DC Conductivity Measurements of Semiconductor Thin films Prepared by Chemical Bath Deposition (CBD) method

Semiconductors have various useful properties that can be exploited for the realization of a large number of high performance devices in fields such as electronics and optoelectronics. Many novel semiconductors, especially in the form of thin films, are continually being developed. Thin films have drawn the attention of many researchers because of their numerous applications. As the film becomes thinner, the properties acquire greater importance in the miniaturization of elements such as resistors, transistors, capacitors, and solar cells. In the present work, copper selenide (CuSe), cadmium selenide (CdSe), zinc selenide (ZnSe), lead sulphide (PbS), zinc sulphide (ZnS), and cadmium sulphide (CdS) thin films were prepared by chemical bath deposition (CBD) method. The prepared thin films were analyzed by using Hall measurements in Van Der Pauw configuration (ECOPIA HMS-3000) at room temperature. The Hall parameters such as Hall mobility of the material, resistivity, carrier concentration, Hall coefficient and conductivity were determined. The DC electrical conductivity measurements were also carried out for the thin films using the conventional two – probe technique. The activation energies were also calculated from DC conductivity studies

ZrO2-based catalysts for biodiesel production: A review

ZrO2-based catalysts are remarkable catalyst with unique advantageous in transesterification and esterification for biodiesel production. Various modifications have been conducted refer to a specified surface properties consist of surface acidity/basicity, specific surface area and porosity, hydrophobicity, and catalysts stability. Summary on the basic concept on catalyst synthesis, applicability for various feedstocks along with their reus�ability aspect in biodiesel production are discussed in this review. Even though the activity of the catalyst is depending on many factors including the oil feedstocks, reaction temperature, molar ratio of oil to methanol, and other conditions, the controllable surface properties of catalyst is a benefit of ZrO2-based catalysts. The recy�clability and reusability of the catalyst become important aspect for developing a sustainable biodiesel pro�duction in the perspective of green chemistry. In addition, future perspective to make sure the applicability of the catalyst for a sustainable process by life cycle assessment is highlighted in this review

Silver Nanoparticles in Various New Applications

The use of silver in antimicrobial management is very ancient. Silver-based materials have proven interesting, practical, and promising for various applications. Silver nanoparticles (AgNPs) have been one of the nanostructures most studied and investigated over the past several years. AgNPs have greater specific properties depending on their size and form. These noble synthesised metrics have numerous optical, electrical, catalytic, and optical characteristics. These properties are ideal for many fields, depending on their size and shape. The outbreak of multiple infectious diseases has been a major strain on global economies and the public health sector. Extensive treatments have been suggested for disease control in environments containing infectious diseases through advanced disinfectant nanomaterials. This chapter investigates the application and mechanism of silver nanoparticles in certain nanobiotechnology sectors as a useful nanomaterial. In the sense of the market statistical survey research, AgNPs are emerging as one of the fastest developing product groups in the nanotechnology industry, providing a wide variety of nanosilver products in various applications. Lastly, due to the massive use of AgNPs in products recently, there are many concerns about AgNPs toxicity and safety had also been discussed

A glassy carbon electrode modified with tailored nanostructures of cobalt oxide for oxygen reduction reaction

Herein we report on various surface morphological characteristics of the synthesized cobalt oxide (Co3O4) nanostructures obtained by means of facile one-step hydrothermal method for oxygen reduction reaction (ORR). The synthesized nanostructures of Co3O4 were adequately characterized by field emission scanning electron microscopy (FESEM) fitted with Energy-dispersive X-ray spectroscopy (EDX) elemental mapping, X-ray diffraction (XRD) and Raman techniques. The electrochemical studies were carried out to analyse the performance of as-synthesized catalysts for ORR by cyclic voltammetry (CV), and chronoamperometric (CA) techniques. A higher electrocatalytic response was observed for Co3O4 nanocubes compared with all the other controlled electrodes by CV with a current density of 0.69 mA/cm2 at a potential value of −0.46 V. The as-synthesized material showed adequate tolerance against methanol observed by CV in the presence of 0.5 M methanol, and good stability when compared with commercial Pt/C catalyst using the CA technique

Recent advances in natural polymer-based hydroxyapatite scaffolds:Properties and applications

New materials that mimic natural bone properties, matching functional, mechanical, and biological properties have been continuously developed to rehabilitate bone defects. Desirably, 'tissue engineering' has been a multidisciplinary ground that uses the principles of life sciences and engineering for the biological replacements that restore or replace the tissue function or a whole organ. Nevertheless, the bone grafting treatment has numerous restrictions, counting the major hazards of morbidity from the sites where donor bone grafts are removed, the likelihood for an immune rejection or bacterial transport from the donor site (in case of allogeneic grafting), and the inadequate availability of donor bone grafts that can meet the current demands. Since the proper growth of synthetic materials for implantable bones encourages the reconstruction of bone tissues by providing strong structural support without any damages to the interferences of biological tissue. To serve for such behavior, the biodegradable matrices provide temporary scaffolds within which the bone tissues can be regenerated. Typically, the thermoplastic aliphatic polyesters are found to serve this purpose. The great significance of this field lies in the in vitro growth of precise cells on porous matrices (scaffolds) to generate three-dimensional (3D) tissues that can be entrenched into the location of tissue/bone damage. Numerous gifts have been gifted by our nature to advance and preserve the well-being of all living things either directly or indirectly. This review focuses on the recent advances in polymer-based hydroxyapatite scaffolds including their properties and applications

Synthesis and process parametric effects on the photocatalyst efficiency of CuO nanostructures for decontamination of toxic heavy metal ions

Among the various environmental pollutants, wastewater from textile dye industries is a major concern. The textile dye industry's effluents contain complex dyes, organic and inorganic salts, acids, and heavy metals which are difficult to decompose in water as they are resistant to biodegradation. Conventional methods for dye removal are not effective due to the nonbiodegradability of dyes and high solubility in water. Photocatalysis is an advanced oxidation process that is effective at degrading recalcitrant organic contaminants. It produces strong reactive oxidants like oxygen or free radical species (hydroxyl radical, and superoxide anion radical) to degrade pollutants into nontoxic molecules Photocatalysis is proposed to be used in conjunction with other treatment processes, such as biological treatments, to reduce total organic carbon, break down macromolecular organic compounds, increased biodegradability, and to reduce the toxicity of water. Through oxidation or reduction reactions, toxic metal ions are converted into their metallic element state, metal oxides, or their valence to nontoxic or lower toxicity. Therefore, the present review focuses on the CuO nanostructures on photocatalytic reduction of metal ions from aqueous media. The impact of synthesis (material) and their process (catalyst, radiation) including the parameters on the photocatalytic activity is overviewed which is the fundamental, and physical source for magnifying the process. Furthermore, the synthesis and process have been discussed in detail considering their impact on eliminating the toxicity of heavy metal ions

Pyrolysis: A Sustainable Way to Generate Energy from Waste

Lignocellulosic biomass is a potentially more valuable renewable resource that can be utilized effusively as a chief source of heat for cooking and can correspondingly subsidize the production of electricity, heat, biofuels and chemicals including solid fuel like char or carbon. Lignocellulosic residues are mixed and burnt with coal to generate electricity. Presently, crude oil is replaced by bioethanol and biodiesel produced from biomass substrate. Some special class of chemicals can be derived from biomass that can subsequently replace the usage of non‐renewable resources of oil and coal. Pyrolysis of woody biomass to obtain pyroliginous acid was started hundreds of years ago, which has versatile applications. The range of products that can be derived from biomass is huge, prompting extent of research using different types of thermal conversion technologies, including pyrolysis, gasification, torrefaction, anaerobic digestion and hydrothermal processing. This chapter provides insights about the stages of reaction during pyrolysis and the outcome of reaction conditions on the products. Technical development and adjustment of process condition can offer a suitable environmentally benign scheme to increase the energy density of the lignocellulosic residues