U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Albert Davydov (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 151 - 172 of 172

High Degree of Crystalline Perfection in Spontaneously Grown GaN Nanowires

January 1, 2006
Author(s)
Kristine A. Bertness, Alexana Roshko, Albert Davydov, Igor Levin, Mark D. Vaudin, Joy Barker, John B. Schlager, Norman Sanford, Larry Robins
We have grown a variety of isolated GaN nanowires using gas-source molecular beam epitaxy (MBE) and characterized their structural and optical properties. The nanowires have demonstrated a number of promising materials characteristics, including low defect

Molecular Beam Epitaxial Growth of High-Quality GaN Nanocolumns

January 1, 2006
Author(s)
J E. Van Nostrand, K L. Averett, R Cortez, J Boecki, C E. Stutz, Norman Sanford, Albert Davydov, J D. Albrecht
Vertically oriented GaN nanocolumns (NCs) approximately 90+10 nm wide and 0.75 microns tall were grown byt plasma-assisted molecular beam epitaxy on Al_(2)O_(3)(0001) and Si(111). The dense packing of the NCs gives them the appearance of a continuous film

Spontaneously grown GaN and AlGaN nanowires

January 1, 2006
Author(s)
Kristine A. Bertness, Alexana Roshko, Norman A. Sanford, Joy Barker, Albert Davydov
We have identified crystal growth conditions in gas-source molecular beam epitaxy (MBE) that lead to spontaneous formation of GaN nanowires with high aspect ratio on Si (1 1 1) substrates. The nanowires were oriented along the GaN c-axis and normal to the

Growth habits and defects in ZnO nanowires grown on GaN/sapphire substrates

August 31, 2005
Author(s)
Igor Levin, Albert Davydov, Babak Nikoobakht, Norman Sanford, Pavel Mogilevsky
Growth habits and defects in epitaxial ZnO nanowires grown from Au catalyst on (00.1) GaN/sapphire substrate using the vapor-liquid-solid (VLS) technique were studied using electron microscopy and x-ray diffraction. The results revealed presence of both

Growth Habits and Defects in ZnO Nanowires Grown on GaN/Sapphire Substrates

August 31, 2005
Author(s)
Igor Levin, Albert Davydov, Babak Nikoobakht, Norman A. Sanford, Pavel Mogilevsky
Growth habits and defects in epitaxial ZnO nanowires grown from Au catalyst on (0001) GaN/sapphire substrate using Vapor-Liquid-Solid (VLS) technique were studied using electron microscopy and X-ray diffraction. The results revealed presence of both

Measurement of Second Order Susceptibilities of GaN and AlGaN

March 1, 2005
Author(s)
Norman Sanford, Albert Davydov, Denis V. Tsvetkov, Vladimir A. Dmitriev, Stacia Keller, Umesh Mishra, Steven P. DenBaars, S S. Park, J H. Han
Rotational Maker fringes, scaled with respect to χ 11 (2) of crystalline quartz, were used to determine the nonlinear optical coefficients χ 31 (2) and χ 33 (2) for samples of thin Al xGa 1-xN films and a bulk free-standing GaN platelet. The Al xGa 1-xN

Fabrication and Analysis of GaN Nanorods grown by MBE

January 1, 2005
Author(s)
Norman Sanford, Larry Robins, Matthew H. Gray, J E. Van Nostrand, C Stutz, R Cortez, Albert Davydov, Alexander J. Shapiro, Igor Levin, Alexana Roshko
GaN nanorods were grown on c-plane sapphire substrates under N-rich conditions by plasma-assisted molecular-beam epitaxy. Scanning electron microsopy revealed densely packed nanorods of hexagonal cross section with diameters ranging from roughly 40 to 100

Refractive index and birefringence of InGaN films grown by MOCVD

January 1, 2005
Author(s)
Norman Sanford, Anneli Munkholm, Mike A. Krames, Alexander J. Shapiro, Igor Levin, Albert Davydov, Safak Sayan, L Wielunski, T E. Madey
The refractive index and birefringence of InxGa1'xN films grown on GaN layers were measured by prism coupling used in conjunction with multilayer optical waveguide analysis. Samples with x = 0.036, 0.049, 0.060, and 0.066 were examined at the separate

Combinatorial Investigation of Structural Quality of Au/Ni Contacts on GaN

June 1, 2004
Author(s)
Albert Davydov, Leonid A. Bendersky, William J. Boettinger, Daniel Josell, Mark D. Vaudin, C S. Chang, Ichiro Takeuchi
A combinatorial library of Au/Ni metalizations on GaN were microstructurally characterized by x-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). The array of single- and bi-layered metal elements

Structural, Electronic and Optical Properties of B-(Fe 1-x Co 2 )Si 2

March 11, 2004
Author(s)
D B. Migas, Leo Miglio, M Rebien, W Henrion, P Stauss, Anthony G. Birdwell, Albert Davydov, V L. Shaposhnikov, V E. Borisenko
Optimized crystal structure, electronic bands and density of states nearby the band gap, and the dielectric function of -(Fe1-xCox)Si2 with x equal to 0.0625 and 0.125 were obtained by means of total energy ultrasoft pseudopotential and full-potential

Controlling The Growth Direction of ZnO Nanowires (NWs) on c and a -Plane Sapphire

February 1, 2004
Author(s)
Babak Nikoobakht, Albert Davydov, Stephan J. Stranick
The issue of controlling the growth direction of NWs is vital in nanotechnology applications and future optoelectronic devices. In an effort to address the above, we have begun studies aimed at selectively controlling the growth direction of horizontal

Refractive Index Study of Al x Ga 1-x N Films Grown on Sapphire Substrates

September 1, 2003
Author(s)
Norman Sanford, Larry Robins, Albert Davydov, Alexander J. Shapiro, Denis V. Tsvetkov, Vladimir A. Dmitriev, Stacia Keller, Umesh Mishra, Steven P. DenBaars
A prism coupling method was used to measure the ordinary (italic}n o) and extraordinary (italic}n e) refractive indices of Al xGa 1-xN films, grown by hydride vapor phase epitaxy (HVPE) and metalorganic chemical vapor deposition (MOCVD) on sapphire, at

Interfacial Reactions of Ti/n-GaN Contacts at Elevated Temperature

July 1, 2003
Author(s)
C J. Lu, Albert Davydov, Daniel Josell, Leonid A. Bendersky
Interfacial reactions in Ti/GaN contacts have been studied using conventional and high-resolution transmission electron microscopy (TEM), energy-filtered TEM (EFTEM) and X-ray diffraction. The thin film contacts were fabricated by evaporating Ti on n-GaN

Revised Thermodynamic Description for the Co-Mo System

June 1, 2003
Author(s)
Albert Davydov, Ursula R. Kattner
The previously assessed Co-Mo system (1999Dav) has been partially revised: thermodynamic descriptions for the liquid, , ς and bcc phases were amended in the attempt to eliminate some unrealistic phase diagram features, such as inverse liquid miscibility

Measurements of the Refractive Indices of MOCVD and HVPE Grown AlGAN Films Using Prism-Coupling Techniques Correlated With Spectroscopic Reflection/Transmission Analysis

January 1, 2003
Author(s)
Norman Sanford, Larry Robins, Albert Davydov, Alexander J. Shapiro, Denis V. Tsvetkov, Vladimir A. Dmitriev, Stacia Keller, Umesh Mishra, Steven P. DenBaars
Waveguide prism-coupling methods were used to measure the ordinary and extraordinary refractive indices of Al xGaN films grown on sapphire substrates by HVPE and MOCVD. Several discrete wavelengths ranging from 442 nm to 1064 nm were used and the results

Characterization of 2.5 Inch Diameter Bulk GaN Grown from Melt-Solution

November 1, 2001
Author(s)
V Soukhoveev, V Ivantsov, Y Melnik, Albert Davydov, Denis Tsvetkov, K Tsvetkova, I Nikitina, A Zubrilov, A Lavrentiev, Vladimir A. Dmitriev
Crystal growth from a melt or melt-solution is a widely accepted technique for industrial-scale production of important semiconductor materials. Recently we have demonstrated 50 mm diameter GaN crystals grown by melt-solution technique [1]. The crystals

Growth of Submicron AlGaN/GaN/AlGaN Heterostructures by Hydride Vapor Phase Epitaxy (HVPE)

November 1, 2001
Author(s)
Denis Tsvetkov, Y Melnik, Albert Davydov, Alexander J. Shapiro, O Kovalenkov, J B. Lam, J J. Song
Multi layer AlGaN/GaN epitaxial structures were grown on SiC by HVPE method. Characterization of the grown structures was performed using SEM, SIMS, mercury probe, electroluminescence and photoluminescence techniques. Thicknesses of nitride layers in the

Thermal Stability of MOCVD and HVPE GaN Layers in H 2 , HCl, NH 3 and N 2

November 1, 2001
Author(s)
M A. Mastro, O M. Kryliouk, M D. Reed, T J. Anderson, Albert Davydov, Alexander J. Shapiro
This work represents a complete study of GaN annealed in H 2, HCl, NH 3 and N 2. The GaN thermal behavior was evaluated by comparison of MOCVD and HVPE samples. The MOCVD films were observed to undergo dissociative sublimation mechanism with only gaseous

Thermodynamic Assessment of the Gallium - Nitrogen System

November 1, 2001
Author(s)
Albert Davydov, William J. Boettinger, Ursula R. Kattner, T J. Anderson
Thermochemical and phase diagram data for the Ga-N system were assessed by employing the CALPHAD method. A consistent model representation of available thermodynamic properties agrees well with the critically evaluated experimental data. Thermodynamic