scholarly journals High spatial resolution picosecond cathodoluminescence of InGaN quantum wells

2006 ◽  
Vol 89 (23) ◽  
pp. 232109 ◽  
Author(s):  
S. Sonderegger ◽  
E. Feltin ◽  
M. Merano ◽  
A. Crottini ◽  
J. F. Carlin ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Ingan Quantum Wells

Cathodoluminescence Studies of InGaN Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
F. A. Ponce ◽  
S. A. Galloway ◽  
W. Goetz ◽  
R. S. Kern
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Light Emission ◽  
Narrow Band ◽  
Photoluminescence Spectra ◽  
Single Quantum ◽  
Band Pass ◽  
Ingan Quantum Wells

AbstractLow temperature cathodoluminescence has been used to investigate the spatial characteristics of light emission in InxGa1−xN single quantum wells. High spatial resolution, narrow band pass imaging shows the luminescence to be strongly inhomogeneous in wavelength as well as in intensity on a sub-micron scale. Cathodoluminescence spectra correlate favorably with photoluminescence spectra. However, when spectra are recorded from different areas in spot mode, the quantum emission varies significantly in wavelength. The observed variations are consistent with composition inhomogeneities in the quantum well.

Electron Energy Loss Spectroscopy (EELS) of GaN Alloys and Quantum Wells

2001 ◽  
Vol 7 (S2) ◽  
pp. 1182-1183
Author(s):  
V. J. Keast ◽  
N. Sharma ◽  
M. Kappers ◽  
C. J. Humphreys
Keyword(s):  
Quantum Wells ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Scanning Transmission Electron Microscope ◽  
Light Emitting ◽  
Quantum Well Structures ◽  
Transmission Electron ◽  
Optical And Electronic Properties ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the last 6-7 years there has been considerable experimental and theoretical interest in GaN and its alloys for use in light emitting applications. GaN is a direct gap semiconductor with a bandgap at ∼ 3.4 eV. When alloyed with in and/or Al the bandgap can be tuned to any wavelength ranging from UV to red. to further the development of GaN based devices, reliable methods are required to measure and predict the optical and electronic properties. EELS is one of the few techniques that can study these properties with high spatial resolution (< 1 nm) if a small electron probe is used, such as that in a scanning transmission electron microscope (STEM). High spatial resolution is necessary as, to improve efficiency, devices are normally based on quantum well structures.

High spatial resolution AEM observations of yttrium segregation in chromia scales grown on Co-45%Cr

1986 ◽  
Vol 44 ◽  
pp. 518-519
Author(s):  
K. Przybylski ◽  
A. J. Garratt-Reed ◽  
G. J. Yurek
Keyword(s):  
Spatial Resolution ◽  
Outer Surface ◽  
Maximum Concentration ◽  
High Spatial Resolution ◽  
Reactive Elements ◽  
Chromia Scales

The addition of so-called “reactive” elements such as yttrium to alloys is known to enhance the protective nature of Cr2O3 or Al2O3 scales. However, the mechanism by which this enhancement is achieved remains unclear. An A.E.M. study has been performed of scales grown at 1000°C for 25 hr. in pure O2 on Co-45%Cr implanted at 70 keV with 2x1016 atoms/cm2 of yttrium. In the unoxidized alloys it was calculated that the maximum concentration of Y was 13.9 wt% at a depth of about 17 nm. SIMS results showed that in the scale the yttrium remained near the outer surface.

Integration of Core-Edge Spectroscopy Methods for the Study of Polymers

1996 ◽  
Vol 54 ◽  
pp. 154-155
Author(s):  
E. G. Rightor
Keyword(s):  
Excited State ◽  
Polymer Blends ◽  
Gas Phase ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Electronic States ◽  
Core Electron ◽  
Bulk Solids ◽  
Development Application

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.

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