Download or read book Expanding the Optical Capabilities of Germanium in the Infrared Range Through Group IV and III V IV Alloy Systems written by Patrick Michael Wallace and published by . This book was released on 2018 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The work described in this thesis explores the synthesis of new semiconductors in the Si-Ge-Sn system for application in Si-photonics. Direct gap Ge1-ySny (y=0.12-0.16) alloys with enhanced light emission and absorption are pursued. Monocrystalline layers are grown on Si platforms via epitaxy-driven reactions between Sn- and Ge-hydrides using compositionally graded buffer layers that mitigate lattice mismatch between the epilayer and Si platforms. Prototype p-i-n structures are fabricated and are found to exhibit direct gap electroluminescence and tunable absorption edges between 2200 and 2700 nm indicating applications in LEDs and detectors. Additionally, a low pressure technique is described producing pseudomorphic Ge1-ySny alloys in the compositional range y=0.06-0.17. Synthesis of these materials is achieved at ultra-low temperatures resulting in nearly defect-free films that far exceed the critical thicknesses predicted by thermodynamic considerations, and provide a chemically driven route toward materials with properties typically associated with molecular beam epitaxy. Silicon incorporation into Ge1-ySny yields a new class of Ge1-x-ySixSny (y>x) ternary alloys using reactions between Ge3H8, Si4H10, and SnD4. These materials contain small amounts of Si (x=0.05-0.08) and Sn contents of y=0.1-0.15. Photoluminescence studies indicate an intensity enhancement relative to materials with lower Sn contents (y=0.05-0.09). These materials may serve as thermally robust alternatives to Ge1-ySny for mid-infrared (IR) optoelectronic applications. An extension of the above work is the discovery of a new class of Ge-like Group III-V-IV hybrids with compositions Ga(As1–xPx)Ge3 (x=0.01-0.90) and (GaP)yGe5–2y related to Ge1-x-ySixSny in structure and properties. These materials are prepared by chemical vapor deposition of reactive Ga-hydrides with P(GeH3)3 and As(GeH3)3 custom precursors as the sources of P, As, and Ge incorporating isolated GaAs and GaP donor-acceptor pairs into diamond-like Ge-based structures. Photoluminescence studies reveal bandgaps in the near-IR and large bowing of the optical behavior relative to linear interpolation of the III-V and Ge end members. Similar materials in the Al-Sb-B-P system are also prepared and characterized. The common theme of the above topics is the design and fabrication of new optoelectronic materials that can be fully compatible with Si-based technologies for expanding the optoelectronic capabilities of Ge into the mid-IR and beyond through compositional tuning of the diamond lattice.
Download or read book Infrared Detectors written by Antonio Rogalski and published by CRC Press. This book was released on 2010-11-15 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: Completely revised and reorganized while retaining the approachable style of the first edition, Infrared Detectors, Second Edition addresses the latest developments in the science and technology of infrared (IR) detection. Antoni Rogalski, an internationally recognized pioneer in the field, covers the comprehensive range of subjects necessary to un
Download or read book Infrared and Terahertz Detectors Third Edition written by Antoni Rogalski and published by CRC Press. This book was released on 2019-01-10 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new edition of Infrared and Terahertz Detectors provides a comprehensive overview of infrared and terahertz detector technology, from fundamental science to materials and fabrication techniques. It contains a complete overhaul of the contents including several new chapters and a new section on terahertz detectors and systems. It includes a new tutorial introduction to technical aspects that are fundamental for basic understanding. The other dedicated sections focus on thermal detectors, photon detectors, and focal plane arrays.
Download or read book Low temperature Far infrared Spectra of Germanium and Silicon written by Peter J. Gielisse and published by . This book was released on 1964 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: New high-resolution low-temperature (7.5K) far-infrared data on intrinsic germanium and silicon are presented. The findings further substantiate the naturally anticipated similarities in band patterns of the vibrational spectra of diamond type crystals. The low temperature spectra of germanium and silicon show clearly resolved splits in their principal absorption bands analogous to the intriguing doublet in the ca. 2000/cm band in diamond. A possible explanation is indicated. The room temperature far-infrared refractive index of both germanium and silicon and the 7.5K refractive index of germanium have been measured by means of interference fringes. (Author).
Download or read book 2D Materials for Infrared and Terahertz Detectors written by Antoni Rogalski and published by CRC Press. This book was released on 2020-10-26 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2D Materials for Infrared and Terahertz Detectors provides an overview of the performance of emerging detector materials, while also offering, for the first time, a comparison with traditional materials used in the fabrication of infrared and terahertz detectors. Since the discovery of graphene, its applications to electronic and optoelectronic devices have been intensively researched. The extraordinary electronic and optical properties allow graphene and other 2D materials to be promising candidates for infrared (IR) and terahertz (THz) photodetectors, and yet it appears that the development of new detectors using these materials is still secondary to those using traditional materials. This book explores this phenomenon, as well as the advantages and disadvantages of using 2D materials. Special attention is directed toward the identification of the most-effective hybrid 2D materials in infrared and terahertz detectors, as well as future trends. Written by one of the world’s leading researchers in the field of IR optoelectronics, this book will be a must-read for researchers and graduate students in photodetectors and related fields. Features • Offers a comprehensive overview of the different types of 2D materials used in fabrication of IR and THz detectors, and includes their advantages/disadvantages • The first book to compare new detectors to a wide family of common, commercially available detectors that use traditional materials.
Download or read book Germanium tin written by Robert Chen and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The germanium-tin (GeSn) alloy system is a highly engineerable, Group-IV material system that has the potential to yield a useful direct bandgap, making it a desirable material for developing light emitters and other photonic devices. Furthermore, its Group-IV nature makes it electronically compatible with silicon and is important for ubiquitous integration into current silicon-based chips. In this dissertation, we explore several properties, features, design, and integration of GeSn alloys on silicon for photonics. Heterostructure devices with GeSn/Ge are developed in quantum-well microdisk resonators and quantum-well light-emitting diodes emitting beyond 2-[mu] m wavelength. Designs, considerations, and strategies towards developing GeSn-based lasers are presented and discussed.
Download or read book Structural Characterization and Optical Properties of Group IV Semiconductor Alloys written by Liying Jiang and published by . This book was released on 2014 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on structural characterizations and optical properties of Si, Ge based semiconductor alloys. Two material systems are characterized: Si-based III-V/IV alloys, which represent a possible pathway to augment the optical performance of elemental silicon as a solar cell absorber layer, and Ge-based Ge1-ySny and Ge1-x-y Six Sny systems which are applicable to long wavelength optoelectronics. Electron microscopy is the primary tool used to study structural properties. Electron Energy Loss spectroscopy (EELS), Ellipsometry, Photoluminescence and Raman Spectroscopy are combined to investigate electronic band structures and bonding properties. The experiments are closely coupled with structural and property modeling and theory. A series of III-V-IV alloys have been synthesized by the reaction of M(SiH3)3 (M = P, As) with Al atoms from a Knudsen cell. In the AlPSi3 system, bonding configurations and elemental distributions are characterized by scanning transmission electron microscopy (STEM)/EELS and correlated with bulk optical behavior.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Growth of Strain Engineered Germanium Tin Alloys for Mid infrared Detectors by Molecular Beam Epitaxy written by Ryan Hickey and published by . This book was released on 2018 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in near and mid-infrared optoelectronic devices for sensing, security, medical imaging, and telecommunications has led to an immense effort to create new materials capable of filling these needs. As the applications for these infrared devices have become more ubiquitous, so too does the desire for cheaper and more efficient materials to meet the demand. As the industry pushes more towards complete device integration, there is also a heavy push specifically towards developing materials compatible with standard CMOS processing. To that end, the alloying of Tin with Germanium and Silicon has been shown to fit these requirements. ☐ During the course of this research on germanium-tin semiconductors, novel methods were developed for growing and fabricating electrical and optical devices with unusually high tin compositions, using silicon-compatible technology. The characteristics and limitations of the devices were measured and analyzed to understand their fundamental properties and to determine how well their performance compared to expectations from current theory. With increasing tin content, the optical devices exhibited a useful direct energy bandgap, which is unique compared to other Group-IV materials, and with operation extended from the near-infrared into the important mid-infrared wavelength regime, even into the long-wave infrared region. The performance of electronic devices, however, was less encouraging, and exhibited low carrier mobilities and high reverse leakage currents. These electrical properties were found partly due to the intrinsic narrow bandgap energy of germanium-tin, but also to the presence of background impurities and dopants, which it may be possible to reduce by using high purity materials and procedures that are compatible with the required low temperature epitaxy.
Download or read book Strain Engineering Germanium tin in Group IV Photonics written by Colleen Shang Fenrich and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The scaling of technology nodes to smaller length scales has enabled unprecedented growth for silicon integrated circuits (IC). The reduction of critical feature dimensions has allowed larger densities of integrated components and improved performance on the device level. At the same time, however, scaling has presented increasing challenges for the performance of global electrical interconnects, which comprise the longest wire lengths on a chip. One solution to overcoming the limitations of electrical interconnect technology is the integration of optical interconnects. While optical communications has already been employed on much larger length scales, the application of optical interconnects for chip-to-chip and on-chip communications has yet to be realized. In the IC industry, the silicon (Si) complementary metal-oxide-semiconductor (CMOS) platform has unified and enabled large-scale integration, but Si performs poorly as an active optical material due to its indirect band gap. As a result, an integrated Si laser has remained elusive in Si photonics, although the ability to leverage this platform for photonic integration has the potential to achieve low cost and high-throughput manufacturing, while maintaining compatibility with CMOS electronics. Developing a tunable direct band gap group IV semiconductor can instead be achieved using the binary germanium-tin system. The incorporation of Sn into the Ge crystal reduces the energy difference between the direct and indirect conduction band minima. A major challenge of the germanium-tin system is lattice mismatch with respect to Si or Ge-buffered Si substrates. Significant compressive strain arises from the coherent epitaxial growth of germanium-tin on these substrates, which inhibits the onset of the fundamental direct gap. This dissertation explores methods of strain engineering pseudomorphic germanium-tin epitaxy to relieve lattice mismatch strain that inhibits the onset of the fundamental direct band gap.
Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Selected Papers on Semiconductor Infrared Detectors written by Antoni Rogalski and published by SPIE-International Society for Optical Engineering. This book was released on 1992 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical and Electrical Properties of Narrow Gap Germanium tin Alloys with High Tin Contents for Middle and Far Infrared Applications written by Dominic Imbrenda and published by . This book was released on 2018 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Germanium-Tin (GeSn) alloys have received considerable attention because of the interesting electronic properties they possess. The offer a potential route to a direct bandgap group IV semiconductor that is isoelectronic with silicon and can be fully integrated into current silicon manufacturing processes. Despite the active research of GeSn some of their optical and electrical properties, especially for the high Sn contents, are not fully understood. ☐ During the course of this research, the optical properties of high Sn content GeSn thin film alloys deposited directly on Ge were determined by variable angle spectroscopic ellipsometry (VASE) from the ultraviolet into the infrared (0.190 – 6 μm). For the first time, the complex dielectric function, complex index of refraction, and absorption coefficient of GeSn alloys with atomic Sn percentages from 15- 27%, are presented. The characterization of the optical properties is important in itself for the development of novel devices but more importantly, they also contain rich information about the electronic bandstructure. Analyzing the second derivative of the dielectric function enables the determination of the energy levels of the critical point transitions in the electronic bandstructure. Second derivative analysis results of the high Sn content films are compared to theoretical predictions and expand on the current predictive models. ☐ Weyl semimetals are a new topological state of matter in semimetals without either spatial inversion or time-reversal symmetry, are characterized by their zero-energy, direct bandgaps, and exhibit novel electronic properties. An active area of research is to determine whether certain materials exhibit the characteristics of a Weyl semimetal. The Sn percentage at which the direct bandgap of GeSn reaches zero is roughly 27%, making it a candidate for a Weyl semimetal at this high Sn percentage. Likely signatures of Weyl semimetals are negative magnetoresistance and photogalvanic current from circularly polarized light. Details and results of these experiments conducted on GeSn are given. Although the results are inconclusive, they open the possibility that high Sn content GeSn alloys belong to this exciting new class of materials.
Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1976 with total page 1052 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science Abstracts written by and published by . This book was released on 1965 with total page 2344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermophysical Properties Research Literature Retrieval Guide Alloys intermetallic compounds and cermets written by Purdue University. Thermophysical Properties Research Center and published by . This book was released on 1973 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
