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Search Publications by: Kris A. Bertness (Fed)

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Displaying 151 - 175 of 178

Interlaboratory comparison of InGaAsP EX-SITU characterization

January 1, 2003
Author(s)
Alexana Roshko, Kristine A. Bertness
A study to improve the accuracy of ex-situ characterization of InGaAsP materials for optoelectronics is underway. Six InGaAsP thin film specimens, with nominal photoluminescence wavelengths of 1.1, 1.3 and 1.5 mm, have been measured, with X-ray diffraction

Trace Water Detection in Phosphine by Cavity Ring-down Spectroscopy

January 1, 2003
Author(s)
Susan Y. Lehman, Kristine A. Bertness, Joseph T. Hodges
We are using cavity ring-down spectroscopy (CRDS) to measure concentrations of water in nitrogen and, for the first time to our knowledge, in phosphine. Water vapor concentrations have been measured in purified and unpurified phosphine, indicating a water

X-ray diffraction, photoluminescence and composition standards of compound semiconductors

January 1, 2003
Author(s)
Alexana Roshko, Kristine A. Bertness, J T. Armstrong, Ryna B. Marinenko, Marc L. Salit, Lawrence H. Robins, Albert J. Paul, R J. Matyi
Work is underway to develop composition standards and standardized assessment procedures for compound semiconductors. An AlGaAs composition standard with less than 2% uncertainty is being developed. The improved accuracy of this standard is being achieved

Composition standards for III-V semiconductor epitaxial films

November 11, 2002
Author(s)
Kristine A. Bertness, Lawrence H. Robins, J T. Armstrong, Ryna B. Marinenko, Albert J. Paul, Marc L. Salit
A program is underway at NIST to establish standard reference materials (SRMs) for the calibration of instruments used to measure the chemical composition of epitaxially grown III-V semiconductor thin films. These SRMs are designed for the calibration of

Ex-situ Characterization of InGaAsP

November 11, 2002
Author(s)
Alexana Roshko, Kristine A. Bertness
An interlaboratory comparison was undertaken to assess differences in X-ray and photoluminescence measurements from different laboratories. Six InGaAsP specimens, with nominal photoluminescence peak wavelengths of 1.1, 1.3 and 1.5 υm, were measured

Trace water detection in semiconductor-grade phosphine gas

November 11, 2002
Author(s)
Kristine A. Bertness, Susan Y. Lehman, Joseph T. Hodges, H. H. Funke, Mark W. Raynor
We are applying cavity ring-down spectroscopy (CRDS) to measure water concentrations in nitrogen and, for the first time to our knowledge, in phosphine. Semiconductor-grade phosphine cylinders from different suppliers contained water in the several ppm

Accuracy of AlGaAs Rates and Composition Determination Using RHEED Oscillations

September 1, 2002
Author(s)
Todd E. Harvey, Kristine A. Bertness, Chih-Ming Wang, Jolene Splett
Reflection high-energy electron diffraction (RHEED) oscillations are widely used in molecular beam epitaxy (MBE) as a technique to calibrate material growth rates. The growth rates are used to predict the composition of the following growth run. For many

Effects of Noise Level in Fitting In-Situ Optical Reflectance Spectroscopy Data

September 1, 2002
Author(s)
Chih-chiang Fu, Kristine A. Bertness, Chih-Ming Wang
We discuss the combination of noise level and scaling factor accuracy needed in optical reflectance spectroscopy data in order to obtain accurate parameters by fitting simulated Optical Reflectance Spectroscopy data curves with different noise level.

InGaAsP Ex-situ characterization

July 1, 2002
Author(s)
Alexana Roshko, Kristine A. Bertness
An interlaboratory comparison has been undertaken of X-ray and photoluminescence measurements of InGaAsP on InP. Six 1 cm 2 specimens are being measured, with nominal photoluminescence wavelengths of 1.1, 1.3 and 1.5 υm (2 of each). Preliminary maps of the

Comparison of AlGaAs oxidation in MBE and MOCVD grown samples

January 1, 2002
Author(s)
Y Chen, Alexana Roshko, Kristine A. Bertness, Dennis W. Readey, Marc A. Mansfield, M. Tan, A. Tandon
Simultaneous wet thermal oxidation of MBE and MOCVD grown Al xGa 1-xAs layers showed that the epitaxial growth method does not influence the oxidation rate. Nearly identical oxidation depths were measured for samples grown by both techniques. It was found

Optoelectronic Device Performance on Reduced Threading Dislocation Density GaAs/Si

April 15, 2001
Author(s)
P. H. Taylor, W. A. Jesser, J. Bradshaw, M. Lara-Taysing, R. P. Leavitt, G. Simonis, W. Chang, W. W. Clark, Kristine A. Bertness
A technique for the heteroepitaxy of GaAs/Si films having reduced threading dislocation density is presented. The important attribute of this technique is the suppression of three-dimensional Volmer-Weber island formation during initial deposition. This

AlGaAs Composition Measurements from In Situ Optical Reflectance

July 1, 2000
Author(s)
Kristine A. Bertness, J T. Armstrong, Ryna B. Marinenko, Larry Robins, Albert J. Paul, Joseph G. Pellegrino, Paul M. Amirtharaj, Deane Chandler-Horowitz
We measure the composition of AlGaAs layers during epitaxial crystal growth using in situ normal-incidence optical reflectance supported by independent methods of measuring growth rate. The results are compared with conventional ex situ characterization.

Compound semiconductor oxide antireflection coatings

May 15, 2000
Author(s)
K. J. Knopp, Richard Mirin, Kristine A. Bertness, Kevin L. Silverman, David H. Christensen
We report the development of high quality, broad-bandwidth, antireflection (AR) coatings using the low index provided by wet thermally oxidized Al 0.98Ga 0.02As. We address the design criteria, fabrication, and characterizations of AR coatings composed of

In Situ Atomic Absorption Monitoring with Substrate Reflection

January 1, 2000
Author(s)
S. P. Hays, Robert K. Hickernell, Kristine A. Bertness
We demonstrate a technique to apply real-time optical flux monitoring by in situ atomic absorption when the only available optical path through a molecular beam epitaxial growth chamber reflects from the substrate. Thin-film interference effects in the

External Radiative Quantum Efficiency of 96 % from a GaAs/GaInP Heterostructure

March 1, 1999
Author(s)
H G. Gauck, T H. Gforerer, M J. Renn, Eric A. Cornell, Kristine A. Bertness
GaAs/GaInP double heterostructures are index matched with ZnSe hemispheres to increase the coupling of photoluminescence out of the device. We measure external quantum efficiencies as large as 96 % using a bolometric calibration technique. When the

High-speed > 90 % quantum-efficiency p-i-n photodiodes with a resonance wavelength adjustable in the 795-835 range

February 22, 1999
Author(s)
E. Vzbay, I. Kimukin, N. Biyikli, O. Ayt|r, M. Gvkkavas, G. Ulu, M. S. {Umlat}nl{umlat}, Richard Mirin, Kristine A. Bertness, David H. Christensen
We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p-i-n photodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we tuned the resonance wavelength from

Optical constants of (Al 0.98 Ga 0.02 ) x O y native oxides

December 14, 1998
Author(s)
K. J. Knopp, Richard Mirin, David H. Christensen, Kristine A. Bertness, Alexana Roshko, R A. Synowicki
We report the optical constants of oxidized crystalline and low-temperature-grown (LTG) Al 0.98Ga 0.02As films, as determined by variable angle spectroscopic ellipsometry. Data were acquired at three angles of incidence over 240-1700nm and fit to a Cauchy

High bandwidth-efficiency resonant cavity enhanced Schottky photodiodes for 800-850 nm wavelength operation

May 25, 1998
Author(s)
M. S. {Umlat}nl{umlat}, M. Gvkkavas, B. M. Onat, E. Ata, E. Vzbay, Richard Mirin, K. J. Knopp, Kristine A. Bertness, David H. Christensen
High-speed resonant cavity enhanced Schottky photodiodes operating in 800-850 nm wavelength region are demonstrated. The devices are fabricated in the AlGaAs/GaAs mate1ial system. The Schottky contact is a semitransparent Au film which also serves as the