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Displaying 76 - 86 of 86

Spontaneous Compositional Modulation in the A1GaN Layers of a Thick A1GaN/GaN Multilayer Structure

January 1, 2001

Author(s)

Igor Levin, Lawrence H. Robins, Mark D. Vaudin, J A. Tuchman, E Lakin, M J. Sherman, J Ramer

A periodic modulation with the wavevector parallel to the [0001] direction was observed in the AlGaN layers of a thick AlGaN/GaN multilayer heterostructure grown by metalorganic chemical vapor disposition. The modulation was attributed to a nearly

Optical and Structural Studies of Compositional Inhomogeneity in Strain-Relaxed Indium Gallium Nitride Films

December 31, 2000

Author(s)

Larry Robins, J T. Armstrong, Ryna B. Marinenko, Mark D. Vaudin, Charles E. Bouldin, J C. Woicik, Albert J. Paul, W. R. Thurber

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.

A Comparison of Aluminum Nitride Freely Nucleated and Seeded on 6H-Silicon Carbide

January 1, 2000

Author(s)

J H. Edgar, Larry Robins, S E. Coatney, L Liu, J Chaudhuri, K Ignatiev, Z J. Rek

The crystal structure and optical properties of AlN single crystals prepared by the sublimation-recondensation method were analyzed by cathodoluminescence (CL) spectroscopy, Raman spectroscopy, and synchrotron white-beam x-ray topography (SWBXT). Needles

Optical Band Gap Dependence on Composition and Thickness of In x Ga 1-x N(0 less than} x less than} 0.25) Grown on GaN

October 1, 1999

Author(s)

C A. Parker, J C. Roberts, S M. Bedair, M J. Reed, S X. Liu, N A. El-Masry, Larry Robins

Band gap measurements have been carried out in strained and relaxed In xGa 1-xN epilayers with x > 0.25. Values of x were determined from x-ray diffraction (XRD) of relaxed films. Band gaps measured by both Photoluminenscence (PL) and optical transmission

Optical Absorption, Raman, and Photoluminescence Excitation Spectroscopy of Inhomogeneous InGaN Films

January 1, 1999

Author(s)

Lawrence H. Robins, Albert J. Paul, C A. Parker, J C. Roberts, S M. Bedair, E L. Piner, N A. El-Masry

In xGa 1-xN films with x=0.06 to x=0.49 were characterized by optical transmittance, Raman, and photoluminescence excitation spectroscopies. Previous microstructural characterizations detected phase separation only in films with x>0.2. The transmittance