Growth And Characterization Of Molybdenum Disulfide Thin Films

Two-dimensional materials, or materials that are only one atomic layer thick, have seen much research in recent years because of their interesting electrical properties. The first of these materials, graphene, was found to have incredible electrical properties but lacked a bandgap in intrinsic films. Without a bandgap, graphene cannot create transistors that can be shut off. Molybdenum disulfide, however, is a two-dimensional semiconductor with a large bandgap. The main issue of molybdenum disulfide is that synthesized films are a much lower quality than their exfoliated counterparts. For molybdenum disulfide to be able to be used practically, a method of synthesis must be found that can reliably create quality large area monolayer films. In this thesis, three methods of molybdenum disulfide film synthesis are presented. Methods implemented used a tube furnace as a chemical vapor deposition system to evaporate source materials to synthesize thin films of molybdenum disulfide. An exploration into the different synthesis parameters shows optimal conditions for these specific methods. Then a discussion of these different methods is presented by judging films grown by using these methods on relevant criteria. This work shows methods to synthesize large area, polycrystalline, small grain, multilayer films, both intrinsic and doped, and to synthesize small area, single crystal and polycrystalline, monolayer films of molybdenum disulfide.

The objective of this work is to prepare Molybdenum thin films to be used as efficient back contact materials and utilize characterization techniques for the investigation of the growth as well the physical properties of Mo thin films deposited through DC-plasma magnetron sputtering on soda lime glass substrate. The effects of process parameters, such as Ar pressure, deposition power and substrate temperature, on the properties of the deposited films have been studied. These process parameters were optimized to get high conductivity Mo thin films to be used in CIGS based thin films solar cells as a back contact.

Ellipsometry is a powerful tool used for the characterization of thin films and multi-layer semiconductor structures. This book deals with fundamental principles and applications of spectroscopic ellipsometry (SE). Beginning with an overview of SE technologies the text moves on to focus on the data analysis of results obtained from SE, Fundamental data analyses, principles and physical backgrounds and the various materials used in different fields from LSI industry to biotechnology are described. The final chapter describes the latest developments of real-time monitoring and process control which have attracted significant attention in various scientific and industrial fields.

Volume IIIA Basic Techniques Handbook of Crystal Growth, Second Edition Volume IIIA (Basic Techniques), edited by chemical and biological engineering expert Thomas F. Kuech, presents the underpinning science and technology associated with epitaxial growth as well as highlighting many of the chief and burgeoning areas for epitaxial growth. Volume IIIA focuses on major growth techniques which are used both in the scientific investigation of crystal growth processes and commercial development of advanced epitaxial structures. Techniques based on vacuum deposition, vapor phase epitaxy, and liquid and solid phase epitaxy are presented along with new techniques for the development of three-dimensional nano-and micro-structures. Volume IIIB Materials, Processes, and Technology Handbook of Crystal Growth, Second Edition Volume IIIB (Materials, Processes, and Technology), edited by chemical and biological engineering expert Thomas F. Kuech, describes both specific techniques for epitaxial growth as well as an array of materials-specific growth processes. The volume begins by presenting variations on epitaxial growth process where the kinetic processes are used to develop new types of materials at low temperatures. Optical and physical characterizations of epitaxial films are discussed for both in situ and exit to characterization of epitaxial materials. The remainder of the volume presents both the epitaxial growth processes associated with key technology materials as well as unique structures such as monolayer and two dimensional materials. Volume IIIA Basic Techniques Provides an introduction to the chief epitaxial growth processes and the underpinning scientific concepts used to understand and develop new processes. Presents new techniques and technologies for the development of three-dimensional structures such as quantum dots, nano-wires, rods and patterned growth Introduces and utilizes basic concepts of thermodynamics, transport, and a wide cross-section of kinetic processes which form the atomic level text of growth process Volume IIIB Materials, Processes, and Technology Describes atomic level epitaxial deposition and other low temperature growth techniques Presents both the development of thermal and lattice mismatched streams as the techniques used to characterize the structural properties of these materials Presents in-depth discussion of the epitaxial growth techniques associated with silicone silicone-based materials, compound semiconductors, semiconducting nitrides, and refractory materials

Molybdenum disulfide (MoS2) is a semiconductor which is composed of Mo atoms sandwiched between two layers of hexagonal close packed sulfur atoms in a structure similar to graphene. Traditionally, it has been used as a solid lubricant due to its low friction properties and as a hydrodesulfurisation catalyst to lower the sulfur content in natural gas and fuels. Bulk MoS2 were first examined as a possible hydrogen evolution reaction electrocatalyst as early as 1977 by Tributsch et al. However, it was not until about 20 years later that its potential in the hydrogen evolution reaction was fully unveiled. This book discusses the synthesis, properties and industrial applications of molybdenum disulfide.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS)* at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dis semination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all concerned if the printing and distribution of the volumes were handled by an international publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Corporation of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 39 (thesis year 1994) a total of 13,953 thesis titles from 21 Canadian and 159 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this impor tant annual reference work. While Volume 39 reports theses submitted in 1994, on occasion, certain uni versities do report theses submitted in previous years but not reported at the time.

Photoelectrochemical Hydrogen Production describes the principles and materials challenges for the conversion of sunlight into hydrogen through water splitting at a semiconducting electrode. Readers will find an analysis of the solid state properties and materials requirements for semiconducting photo-electrodes, a detailed description of the semiconductor/electrolyte interface, in addition to the photo-electrochemical (PEC) cell. Experimental techniques to investigate both materials and PEC device performance are outlined, followed by an overview of the current state-of-the-art in PEC materials and devices, and combinatorial approaches towards the development of new materials. Finally, the economic and business perspectives of PEC devices are discussed, and promising future directions indicated. Photoelectrochemical Hydrogen Production is a one-stop resource for scientists, students and R&D practitioners starting in this field, providing both the theoretical background as well as useful practical information on photoelectrochemical measurement techniques. Experts in the field benefit from the chapters on current state-of-the-art materials/devices and future directions.