Download or read book Development of Traveling Heater Method to Grow Cadmium Telluride CdTe Cadmium Zinc Telluride CZT Crystals written by Manchanahalli S. Rohan Rao and published by . This book was released on 2011 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation and Growth of Cadmium Zinc Telluride from Small Seeds by the Travelling Heater Method written by Jordan Douglas Roszmann and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The semiconducting compounds CdTe and CdZnTe have important applications in high-energy radiation detectors and as substrates for infrared devices. The materials offer large band gaps, high resistivity, and excellent charge transport properties; however all of these properties rely on very precise control of the material composition. Growing bulk crystals by the travelling heater method (THM) offers excellent compositional control and fewer defects compared to gradient freezing, but it is also much slower and more expensive. A particular challenge is the current need to grow new crystals onto existing seeds of similar size and quality. Simulations and experiments are used in this work to investigate the feasibility of growing these materials by THM without the use of large seed crystals. A new fixed-grid, multiphase finite element model was developed based on the level set method and used to calculate the mass transport regime and interface shapes inside the growth ampoule. The diffusivity of CdTe in liquid tellurium was measured through dissolution experiments, which also served to validate the model. Simulations of tapered THM growth find conditions similar to untapered growth with interface shapes that are sensitive to strong thermosolutal convection. Favourable growth conditions are achievable only if convection can be controlled. In preliminary experiments, tapered GaSb crystals were successfully grown by THM and large CdTe grains were produced by gradient freezing. Beginning with this seed material, 25 mm diameter CdTe and CdZnTe crystals were grown on 10 mm diameter seeds, and 65 mm diameter CdTe on 25 mm seeds. Unseeded THM growth was also investigated, as well as ampoule rotation and a range of thermal conditions and ampoule surface coatings. Outward growth beyond one or two centimeters was achieved only at small diameters and included secondary grains and twin defects; however, limited outward growth of larger seeds and agreement between experimental and numerical results suggest that tapered growth may be achievable in the future. This would require active temperature control at the base of the crystal and reduction of convection through thermal design or by rotation of the ampoule or applied magnetic fields.
Download or read book Developments in Cadmium Zinc Telluride Crystal Growth Sample Preparation and Characterisation sic Techniques written by Amlan Datta and published by . This book was released on 2010 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Modeling of Bulk Crystal Growth of Cadmium Zinc Telluride in Industrial VB VGF Systems written by Arun Pandy and published by . This book was released on 2004 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Application of Cadmium Telluride written by R. H. Williams and published by . This book was released on 1980 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large Single Crystals of CdTe were grown by the methods of Liquid Encapsulated Czochralski, Fast Vertical Bridgman, Travelling Heater Method, Stockbarger method. Electrical characterization was done by Seebeck, Hall Effect and Conductivity measurements. Surfaces were investigated using XPS, UPS, AES and LEED. Metal-CdTe contacts were fabricated. Formation of these was monitored using XPS, UPS, LEED, AES. Barrier Heights were established by I-V, C-V and UPS measurements. Results show that the effect of the CdTe surface on the type of contact formed is very marked. (Author).
Download or read book Modeling and Control of Cadmium Zinc Telluride Grown Via an Electro dynamic Gradient Freeze Furnace written by Lisa San Lun and published by . This book was released on 2007 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CdTe and CdZnTe Materials written by Kris Iniewski and published by Springer Nature. This book was released on with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Materials for Radiation Detection written by Krzysztof (Kris) Iniewski and published by Springer Nature. This book was released on 2021-08-05 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers readers an overview of some of the most recent advances in the field of advanced materials used for gamma and X-ray imaging. Coverage includes both technology and applications, with an in-depth review of the research topics from leading specialists in the field. Emphasis is on high-Z materials like CdTe, CZT and GaAs, as well as perovskite crystals, since they offer the best implementation possibilities for direct conversion X-ray detectors. Authors discuss material challenges, detector operation physics and technology and readout integrated circuits required to detect signals processes by high-Z sensors.
Download or read book Optimization of Cadmium Zinc Telluride Crystal Growth for Room Temperature Radiation Detectors written by Kelly Allan Jones and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improved Techniques for the Growth of High Quality Cadmium Telluride Crystals written by R. S. Feigelson and published by . This book was released on 1985 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes two years' work as part of a multiyear program on improved techniques for the growth of high quality cadmium telluride crystals and represents one of the most comprehensive studies of melt growth and defect characterization in CdTe reported to date. Extensive melt growth studied were carried out using te vertical Bridgman method. Growth parameters were systematically varied in order to determine the influence of seed orientation, thermal environment, and growth rate on crystal quality. Growth interface shapes were revealed using autoradiographic dopant tracing methods. Melt thermal profiling was also carried out to further evaluate growth interface shapes. Controlled convex growth interface shapes were generated by using the heat exchanger method. By this means some improvement in grain structure of the typically polycrystalline boules was accomplished. Low frequency melt vibrations during growth were also observed to improve grain structure and reduce dislocation density. Extensive defect characterization was alos carried out using chemical etching methods, and later, synchrotron x-ray topography. Comparative studies of a broad selection of commercial CdTe substrates was carried out, and extensive defect structure was observed in all cases. Reduced dislocation densities and defect structures were accomplished using both low amplitude melt vibrations and doping with In 1IIC13. In the second case, solution hardening was assumed to be the mechanism responsible. For the case of melt vibration, the mechanism is not yet understood.
Download or read book Research and Development on Single Crystal High Resistivity Cadmium Telluride for Use as a Gamma ray Spectrometer written by Kenneth R. Zanio and published by . This book was released on 1971 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Radioactivity Analysis written by Michael F. L'Annunziata and published by Academic Press. This book was released on 2020-03-03 with total page 1110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Radioactivity Analysis: Radiation Physics and Detectors, Volume One, and Radioanalytical Applications, Volume Two, Fourth Edition, is an authoritative reference on the principles, practical techniques and procedures for the accurate measurement of radioactivity - everything from the very low levels encountered in the environment, to higher levels measured in radioisotope research, clinical laboratories, biological sciences, radionuclide standardization, nuclear medicine, nuclear power, and fuel cycle facilities, and in the implementation of nuclear forensic analysis and nuclear safeguards. It includes sample preparation techniques for all types of matrices found in the environment, including soil, water, air, plant matter and animal tissue, and surface swipes.Users will find a detailed discussion of our current understanding of the atomic nucleus, nuclear stability and decay, nuclear radiation, and the interaction of radiation with matter relating to the best methods for radionuclide detection and measurement. - Spans two volumes, Radiation Physics and Detectors and Radioanalytical Applications - Includes a much-expanded treatment of calculations required in the measurement of radionuclide decay, energy of decay, nuclear reactions, radiation attenuation, nuclear recoil, cosmic radiation, and synchrotron radiation - Includes the latest advances in liquid and solid scintillation analysis, alpha- and gamma spectrometry, mass spectrometric analysis, gas ionization and nuclear track analysis, and neutron detection and measurement - Covers high-sample-throughput microplate techniques and multi-detector assay methods
Download or read book Study on Thermal Annealing of Cadmium Zinc Telluride CZT Crystals written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cadmium Zinc Telluride (CZT) has attracted increasing interest with its promising potential as a room-temperature nuclear-radiation-detector material. However, different defects in CZT crystals, especially Te inclusions and dislocations, can degrade the performance of CZT detectors. Post-growth annealing is a good approach potentially to eliminate the deleterious influence of these defects. At Brookhaven National Laboratory (BNL), we built up different facilities for investigating post-growth annealing of CZT. Here, we report our latest experimental results. Cd-vapor annealing reduces the density of Te inclusions, while large temperature gradient promotes the migration of small-size Te inclusions. Simultaneously, the annealing lowers the density of dislocations. However, only-Cd-vapor annealing decreases the resistivity, possibly reflecting the introduction of extra Cd in the lattice. Subsequent Te-vapor annealing is needed to ensure the recovery of the resistivity after removing the Te inclusions.
Download or read book Strategic Approaches Towards Solving Critical Challenges in Crystal Growth of Detector Grade Cd0 9Zn0 1Te Including Melt Mixing Techniques written by Amlan Datta and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades Cadmium Zinc Telluride (CZT) has emerged as a novel material for radiation detection in homeland security as well as medical applications and as substrates for epitaxial growth of infrared detector, Mercury Cadmium Telluride. There are, however, several critical issues regarding the bulk growth of CZT which renders it unsuitable or cost ineffective for these applications. These challenges can be summarized as non-uniformity (due to Zinc and intentional dopant segregation), longer growth times (because of lower thermal conductivity of the melt), Tellurium (Te) secondary phases (SP), unstable growth interface (due to lower thermal conductivity and higher heat of fusion) and non-stoichiometric growth conditions. Systematic approaches towards solving these problems will be discussed along with the consequences and future research directions.
Download or read book High Z Materials for X ray Detection written by Leonardo Abbene and published by Springer Nature. This book was released on 2023-01-01 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will provide readers with a good overview of some of most recent advances in the field of High-Z materials. There will be a good mixture of general chapters in both technology and applications in opto-electronics, X-ray detection and emerging optoelectronics applications. The book will have an in-depth review of the research topics from world-leading specialists in the field.
Download or read book Inclusion Free Cadmium Zinc Tellurium and Cadmium Tellurium Crystals and Associated Growth Method written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present disclosure provides systems and methods for crystal growth of cadmium zinc tellurium (CZT) and cadmium tellurium (CdTe) crystals with an inverted growth reactor chamber. The inverted growth reactor chamber enables growth of single, large, high purity CZT and CdTe crystals that can be used, for example, in X-ray and gamma detection, substrates for infrared detectors, or the like. The inverted growth reactor chamber enables reductions in the presence of Te inclusions, which are recognized as an important limiting factor in using CZT or CdTe as radiation detectors. The inverted growth reactor chamber can be utilized with existing crystal growth techniques such as the Bridgman crystal growth mechanism and the like. In an exemplary embodiment, the inverted growth reactor chamber is a U-shaped ampoule.
Download or read book AACGE 2017 Program and Abstract written by AACG and published by Coe Truman International, LLC. This book was released on 2017-07-27 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: AACGE 2017 Program and Abstract - American Conference on Crystal Growth (AACG)
