Download or read book Preparation and Evaluation of ZnSe and ZnS Sub X Se Sub 1 X Epitaxial Layers on Ge Substrates for Applications in Surface Passivation and Heterojunction Devices written by W. E. Stutius and published by . This book was released on 1984 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes a detailed study of ZnSe and ZnSxSe1-x epitaxial growth on germanium and gallium arsenide substrates, for application in surface passivation and heterojunction devices. These layers were prepared by a novel low pressure, low temperature organometallic chemical vapor deposition (OM-CVD) process. Both nominally undoped, intrinsic ZnSe and Al-doped, highly conductive n-type ZnSe were prepared by this method. Excellent epitaxial growth was achieved as indicated by the large intensity in the near bandgap photoluminescence and the rather weak intensity in the self-activated luminescence spectra. This indicates a low concentration of intrinsic and extrinsic defects and a low compensation ratio. An important relationship was observed between reproducibility of layer characteristics and substrate and reactor preparation. Also, deep center luminescence revealed that ZnSe layers deposited on both GaAs and Ge (100) surfaces have luminescence properties superior to those deposited on other substrate orientations. This study revealed a large disparity in the electrical conductivity depending on substrate orientation, of Al-doped, n-type ZnSe layers deposited both on GaAs and Ge Substrates. The defect structure of ZnSe layers grown on (100), (110), and (111)b GaAs, and on (100) and (111) Ge substrates were imaged for the first time by high resolution transmission electron microscopy. ZeSe-Ge heterojunctions were successfully fabricated and reflect the orientation dependent of interface properties and layer resistivity in their current - voltage characteristics.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1985 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 966 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1985-02 with total page 1128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index Keyword A L written by and published by . This book was released on 1985 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 2304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Formation of Buried Epitaxial Si Ge Alloy Layers in Si 100 crystal by High Dose Ge Ion Implantation written by and published by . This book was released on 1991 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have synthesized single crystal Si{sub 1-x}Ge(subscript x) alloy layers in Si 100 crystals by high dose Ge ion implantation and solid phase epitaxy. The implantation was performed using the metal vapor vacuum arc (Mevva) ion source. Ge ions at mean energies of 70 and 1000 keV and with doses ranging from 1 x 1016 to 7 x 1016 ions/cm2 were implanted into Si 100 crystals at room temperature, resulting in the formation of Si{sub 1-x}Ge(subscript x) alloy layers with peak Ge concentrations of 4 to 13 atomic %. Epitaxial regrowth of the amorphous layers were initiated by thermal annealing at temperatures higher than 500°C. The solid phase epitaxy process, the crystal quality, microstructures, interface morphology and defect structures were characterized by ion channeling and transmission electron microscopy. Compositionally graded single crystal Si{sub 1-x}Ge(subscript x) layers with full width at half maximum (approximately)100nm were formed under a (approximately)30nm Si layer after annealing at 600°C for 15 min. A high density of defects was found in the layers as well as in the substrate Si just below the original amorphous/crystalline interface. The concentration of these defects was significantly reduced after annealing at 900°C. The kinetics of the regrowth process, the crystalline quality of the alloy layers, the annealing characteristics of the defects, and the strains due to the lattice mismatch between the alloy and the substrate are discussed.

Download or read book Growth and Characterization of ZnSe ZnSxSe1 x Heterostructures on Si Substrates by Atomic Layer Epitaxy written by and published by . This book was released on 2000 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ceramic Abstracts written by and published by . This book was released on 1998 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ge subscript x Si subscript 1 x epitaxial layers grown by rapid thermal processing chemical vapor deposition written by Kim Hsi-I Jung and published by . This book was released on 1989 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth of Epitaxial ZnS ZnSe and ZnSe1 minus X S x Alloy Thin Films Multilayers and Superlattices by Pulsed laser Ablation written by James Wilson McCamy and published by . This book was released on 1993 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of ZnSe and ZnSxSe1 x for Application in Thin Film Solar Cells written by Stephen Armstrong and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: AbstractSuccessful deposition of ZnSe and ZnS?Sei_x layers has been performed with close-spaced thermal evaporation (CSTE). ZnSe (Eg = 2.67eV) and ZnS, Sei, (Eg to 3.6eV) have the potential to replace CdS (Eg = 2.42 eV) as a buffer layer in solar cell applications, giving a two-fold benefit: (i) increased blue response of the cell, potentially allowing more light to reach the pn junction and contribute to photogeneration and (ii) reduce the toxic Cd element of the buffer layer. CSTE has produced films in which the deposition parameters can be controlled to alter the morphology of the as-deposited coatings. SEM and AFM investigations have shown that pinhole free ZnSe and ZnS?Sei_x films can be produced with this deposition process. In addition, the ZnSxSei, layers show a linear shift in lattice constant and a systematic shift in energy bandgap with alloy composition. XRD data and the steep absorption edges in the transmittance data confirm the good crystallinity of the layers. To partner the ZnSe and ZnS, Sei_x buffer layers in a thin film heterojunction, CdTe absorber layers were grown in the superstrate configuration. These CdTe layers were deposited in the same deposition chamber, without breaking vacuum, to reduce the risk of interfacial contamination. ZnSe and ZnSxSei_x / CdTe solar cells were fabricated with the best cell producing PV characteristics of: short circuit current 17mAcm-2, open circuit voltage 460mV and efficiency approaching 3%. The spectral response of all ZnSe and ZnSxSei_x / CdTe devices demonstrated a systematic shift to shorter wavelengths with increasing alloy composition, therefore showing the potential of these materials to increase solar cell efficiency. This low cost deposition process has shown excellent potential to be scaled up for commercial applications.

Download or read book Epitaxial Growth and Characterization of Si 1 x Ge x Materials and Devices written by Pallab Bhattacharya and published by . This book was released on 1997 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project were the understanding of heteroepitaxial growth of SiGe/Si, dislocation control for highly mismatched layers, and the application of such heterostructures to high speed microelectronics and optoelectronics. A new technique of dislocation control, using a low-temperature Si buffer layer, has been identified. SiGe/Si heterostructure FETs have been fabricated, using this technique. Heterostructure bipolar transistors have been utilized to realize the first SiGe-based integrated photoreceivers. The electro-optic coefficients in SiGe/Si quantum wells have also been measured. Modulators, whose operation principle is based on the small conduction band offset, in this heterostructure, has been demonstrated theoretically and experimentally, for the first time. Theoretical work, involving a charge control study of the interfacial effects in p-MOSFETs.

Download or read book Epitaxial Pb Zr sub X Ti sub 1 minus x O sub 3 SrRuO sub 3 x written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Epitaxial SrRuO[sub 3] thin films were deposited on SrTiO[sub 3](100) and MgO(100) substrates by RF sputtering for use as bottom electrodes and epitaxial buffer layers. On these conductive substrates, epitaxial Pb(Zr[sub x]Ti[sub 1[minus]x])O[sub 3] (PZT; x= 0.35,0.65) and PbTiO[sub 3] (PT; x= 0) thin films were deposited by metalorganic chemical vapor deposition (MOCVD). X-ray diffraction (XRD), RBS channeling (RBS), transmission electron microscopy (TEM) and optical waveguiding were used to characterize the phase, microstructure, defect structure, refractive index, and film thickness of the deposited films. The PZT and PT films were epitaxial and c-axis oriented. 90[degree] domains, interfacial misfit dislocations and threading dislocations were the primary structural defects, and the films showed as high as a 70% RBS channeling reduction. Ferroelectric hysteresis and dielectric measurements of epitaxial PZT ferroelectric capacitor structures formed using evaporated Ag top electrode showed: a remanent polarization of 46.2[mu]C/cm[sup 2], a coercive field of 54.9 kV/cm, a dielectric constant of 410, a bipolar resistivity of[approximately]5.8[times] 10[sup 9][Omega]-cm at a field of 275 kV/cm, and a breakdown strength of>400 kV/cm. Cyclic fatigue measurements showed that the remanent polarization was maintained for>10[sup 9] cycles.

Download or read book The Materials Science of Thin Films written by Milton Ohring and published by Academic Press. This book was released on 1992 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prepared as a textbook complete with problems after each chapter, specifically intended for classroom use in universities.

Download or read book Photovoltaic and Photoactive Materials written by Joseph M. Marshall and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this NATO Advanced Study Institute (ASI) was to present an up-to-date overview of various current areas of interest in the field of photovoltaic and related photoactive materials. This is a wide-ranging subject area, of significant commercial and environmental interest, and involves major contributions from the disciplines of physics, chemistry, materials, electrical and instrumentation engineering, commercial realisation etc. Therefore, we sought to adopt an inter disciplinary approach, bringing together recognised experts in the various fields while retaining a level of treatment accessible to those active in specific individual areas of research and development. The lecture programme commenced with overviews of the present relevance and historical development of the subject area, plus an introduction to various underlying physical principles of importance to the materials and devices to be addressed in later lectures. Building upon this, the ASI then progressed to more detailed aspects of the subject area. We were also fortunately able to obtain a contribution from Thierry Langlois d'Estaintot of the European Commission Directorate, describing present and future EC support for activities in this field. In addition, poster sessions were held throughout the meeting, to allow participants to present and discuss their current activities. These were supported by what proved to be very effective feedback sessions (special thanks to Martin Stutzmann), prior to which groups of participants enthusiastically met (often in the bar) to identify and agree topics of common interest.

Download or read book Semiconductor Laser Engineering Reliability and Diagnostics written by Peter W. Epperlein and published by John Wiley & Sons. This book was released on 2013-01-25 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performance- and reliability-impacting factors such as temperature, stress and material instabilities. Further key features include: practical design guidelines that consider also reliability related effects, key laser robustness factors, basic laser fabrication and packaging issues; detailed discussion of diagnostic investigations of diode lasers, the fundamentals of the applied approaches and techniques, many of them pioneered by the author to be fit-for-purpose and novel in the application; systematic insight into laser degradation modes such as catastrophic optical damage, and a wide range of technologies to increase the optical strength of diode lasers; coverage of basic concepts and techniques of laser reliability engineering with details on a standard commercial high power laser reliability test program. Semiconductor Laser Engineering, Reliability and Diagnostics reflects the extensive expertise of the author in the diode laser field both as a top scientific researcher as well as a key developer of high-power highly reliable devices. With invaluable practical advice, this new reference book is suited to practising researchers in diode laser technologies, and to postgraduate engineering students.