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Displaying 1 - 25 of 86

Optical and Structural Studies of Strain-Relaxed InxGa1-xN Films on GaN/sapphire with 0.04 0.47

February 19, 2017
Author(s)
Larry Robins, J T. Armstrong, Mark D. Vaudin, Charles E. Bouldin, Joseph Woicik, Albert J. Paul, W. R. Thurber, Ryna B. Marinenko
The structures of a set of InxGa1-xN films grown by atmospheric-pressure MOCVD onGaN buffer layers on c-plane sapphire, with compositions in the range 0.04 x 0.47, were characterized by x-ray diffraction (XRD). Several films were also examined by

Raman spectroscopy based measurements of carrier concentration in n-type GaN nanowires grown by plasma-assisted molecular beam epitaxy

September 30, 2016
Author(s)
Lawrence H. Robins, Elizabeth Horneber, Norman A. Sanford, Kristine A. Bertness, John B. Schlager
The carrier concentration in ensembles of n-type GaN nanowires (NWs) grown by plasma-assisted molecular beam epitaxy was determined by curve-fitting analysis of Raman spectra, based on modeling of the carrier concentration dependence of the longitudinal

Studies of photoconductivity and FET behavior in examining drift mobility, surface depletion, and transient effects in Si-doped GaN nanowires examined in vacuum and air

May 3, 2013
Author(s)
Norman A. Sanford, Lawrence H. Robins, Paul T. Blanchard, K. Soria, B. Klein, Kristine A. Bertness, John B. Schlager, Aric W. Sanders
Variable intensity photoconductivity (PC) performed under vacuum at 325 nm was used to estimate drift mobility and negative surface charge density sigma for c-axis oriented Si-doped GaN nanowires (NWs). In this approach we assumed that sigma was

Improved Performance of Schottky Diodes on Pendeo-Epitaxial Gallium Nitride

September 1, 2008
Author(s)
Lawrence H. Robins, T Zheleva, M Derenge, D Ewing, P Shah, K Jones, U Lee
We designed experiments to investigate the role of the dislocation density on the performance of Schottky diodes fabricated on GaN material grown conventionally and by pendeo-epitaxy. Devices of varying geometries were fabricated on the low defect density

Steady-state and time-resolved photoluminescence from relaxed and strained GaN nanowires grown by catalyst-free molecular-beam epitaxy

June 24, 2008
Author(s)
John B. Schlager, Kristine A. Bertness, Paul T. Blanchard, Lawrence H. Robins, Alexana Roshko, Norman A. Sanford
We report steady-state and time-resolved photoluminescence (TRPL) measurements on individual GaN nanowires (6-20 micrometers in length, 30-940 nm in diameter) grown by nitrogen-plasma-assisted, catalyst-free MBE on Si(111) and dispersed onto fused quartz

Optical and structural study of GaN nanowires grown by catalyst-free molecular beam epitaxy. II. Sub-band-gap luminescence and electron irradiation effects

June 4, 2007
Author(s)
Larry Robins, Kristine A. Bertness, Joy Barker, Norman Sanford, John B. Schlager
GaN nanowires with diameters of 50-250nm, grown by catalyst-free molecular beam epitaxy, were characterized by photoluminescence (PL) and cathodoluminescence (CL) spectroscopy at temperatures from 3 to 297 K. Both as-grown samples and dispersions of