New PbSnTe heterojunction laser diode structures with improved performance

Several recent advances in the state-of-the-art of lead tin telluride double heterojunction laser diodes are summarized. Continuous Wave operation to 120 K and pulsed operation to 166 K with single, lowest order transverse mode emission to in excess of four times threshold at 80 K were achieved in buried stripe lasers fabricated by liquid phase epitaxy in the lattice-matched system, lead-tin telluride-lead telluride selenide. At the same time, liquid phase epitaxy was used to produce PbSnTe distributed feedback lasers with much broader continuous single mode tuning ranges than are available from Fabry-Perot lasers. The physics and philosophy behind these advances is as important as the structures and performance of the specific devices embodying the advances, particularly since structures are continually being evolved and the performance continues to be improved

Growth of InP on GaAs (001) by hydrogen-assisted low-temperature solid-source molecular beam epitaxy

Direct heteroepitaxial growth of InP layers on GaAs (001) wafers has been performed by solid-source molecular beam epitaxy assisted by monoatomic hydrogen (H∗). The epitaxial growth has been carried out using a two-step method: for the initial stage of growth the temperature was as low as 200 °C and different doses of H∗ were used; after this, the growth proceeded without H∗ while the temperature was increased slowly with time. The incorporation of H∗ drastically increased the critical layer thickness observed by reflection high-energy electron diffraction; it also caused a slight increase in the luminescence at room temperature, while it also drastically changed the low-temperature luminescence related to the presence of stoichiometric defects. The samples were processed by rapid thermal annealing. The annealing improved the crystalline quality of the InP layers measured by high-resolution x-ray diffraction, but did not affect their luminescent behavior significantly

Quantum Electronics

Contains report on ten research projects split into three sections.Joint Services Electronics Program (Contract DAAG29-78-C-0020)National Science Foundation (Grant PHY77-07156)U. S. Air Force-Office of Scientific Research (Grant AFOSR-3042)National Science Foundation (Grant ENG77-24981

Global Relationships Between River Width, Slope, Catchment Area, Meander Wavelength, Sinuosity, and Discharge

Using river centerlines created with Landsat images and the Shuttle Radar Topography Mission digital elevation model, we created spatially continuous maps of mean annual flow river width, slope, meander wavelength, sinuosity, and catchment area for all rivers wider than 90 m located between 60°N and 56°S. We analyzed the distributions of these properties, identified their typical ranges, and explored relationships between river planform and slope. We found width to be directly associated with the magnitude of meander wavelength and catchment area. Moreover, we found that narrower rivers show a larger range of slope and sinuosity values than wider rivers. Finally, by comparing simulated discharge from a water balance model with measured widths, we show that power laws between mean annual discharge and width can predict width typically to −35% to +81%, even when a single relationship is applied across all rivers with discharge ranging from 100 to 50,000 m3/s

Quantum Electronics

Contains research objectives and summary of research on eight research projects split into four sections.Joint Services Electronics Program (Contract DAAB07-76-C-1400)U. S. Air Force - Office of Scientific Research (Grant AFOSR-76-3042)U. S. Air Force - Office of Scientific Research (Contract F44620-76-C-0079

High-Frequency (> 100 GHz) Electronic Devices

Contains reports on five research projects and a list of publications.MIT Lincoln LaboratoryNational Aeronautics and Space Administration Grant NAG2-693National Science Foundation Grant ECS 91-09330Defense Advanced Research Projects Agency Contract MDA972-90-C-0021U.S. Army - Research Office Grant DAAL03-92-G-025

Quantum Electronics

Contains thirteen research projects split into three sections.U.S. Air Force - Rome Air Development Center (Contract F19628-80-C-0077)National Science Foundation (Grant PHY79-09739)Joint Services Electronics Program (Contract DAAG29-78-C-0020)Joint Services Electronics Program (Contract DAAG29-80-C-0104)U.S. Air Force Geophysics Laboratory (AFSC) (Contract F19628-79-C-0082)National Science Foundation (Grant ECS79-19475)National Science Foundation (Grant DAR80-08752)National Science Foundation (Grant ENG79-09980

High-Frequency (> 100 GHz) Electronic Devices

Contains reports on four research projects, the research facility and a list of publications.Defense Advanced Research Projects Agency Contract MDA972-90-C-0021National Aeronautics and Space Administration Grant NAG2-693National Science Foundation Grant ECS 91-0933

Quantum Electronics

Contains reports on three research projects.National Science Foundation (Grant PHY77-07156)Joint Services Electronics Program (Contract DAABO7-76-C-1400)U. S. Air Force - Office of Scientific Research (Grant AFOSR-76-3042)U. S. Air Force - Office of Scientific Research (Contract F-44620-76-C-0079)M.I.T. Sloan Fund for Basic Researc