Algorithm for evaluating layer thickness based on electron average energy shift analysis

2012 ◽  
Vol 288 ◽  
pp. 23-27 ◽  
Author(s):  
A. Givon ◽  
E. Tiferet ◽  
I. Orion
Keyword(s):  
Layer Thickness ◽  
Average Energy ◽  
Energy Shift ◽  
Shift Analysis

Characterization and Griwth of Oicanic Multiple Qanm Well Structures

1990 ◽  
Vol 198 ◽  
Author(s):  
F.F. So ◽  
S.R. Forrest ◽  
Y.Q. Shi ◽  
W.H. Steier
Keyword(s):  
Quantum Well ◽  
Layer Thickness ◽  
Organic Semiconductors ◽  
Multiple Quantum Well ◽  
Energy Shift ◽  
Blue Shift ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Singlet Exciton ◽  
Molecular Beam Deposition

ABSTRACTMultiple quantum well structures consisting of alternating layers of two crystalline organic semiconductors, namely, 3,4,9,10 perylenetetracarboxylic dianhydride (PTCDA) and 3,4,7,8 naphthalenetetracarboxylic dianhydride (NTCDA), have been grown by organic molecular beam deposition. The layer thickness was varied from 10 to 200 Å. Birefringence measurements indicate that there is a strong structural ordering in all PrCDA layers, although the PrCDA and NTCDA crystal structures are incommensurate. From optical absorption measurements, it is found there is a blue shift in the lowest energy PICDA singlet exciton line with decreasing layer thickness. A model based on exciton quantum confinement is proposed to explain the energy shift. We have measured the low temperature photoluminescence spectra of organic quantum well structures, and found a slight red shift in the spectra with decreasing well width. These results are also discussed.

Configuration-average energy shift owing to configuration interaction

1989 ◽  
Vol 39 (9) ◽  
pp. 4599-4609 ◽  
Author(s):  
J. Oreg ◽  
W. H. Goldstein ◽  
A. Bar-Shalom ◽  
M. Klapisch
Keyword(s):  
Configuration Interaction ◽  
Average Energy ◽  
Energy Shift

Layer Thickness Dependence of Strain in GaN grown by HVPE

2001 ◽  
Vol 693 ◽  
Author(s):  
Gyu Gwang Sim ◽  
P. W. Yu ◽  
D. C. Reynolds ◽  
D. C. Look ◽  
Sang Soo Kim ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Strain Relaxation ◽  
Compressive Strain ◽  
Energy Shift ◽  
Thickness Dependence ◽  
Hydride Vapor Phase Epitaxy ◽  
Strain Effect ◽  
Transition Energies ◽  
Sapphire Substrates ◽  
Thermal Expansion Coefficients

AbstractWurzite GaN epilayers on sapphire substrates usually suffer from biaxial compressive strain due to the mismatches of the thermal expansion coefficients and the lattice constants between GaN layers and sapphire substrates. We have investigated the layer thickness effects on strain and transition energies by photoluminescence (PL), photoreflectance (PR) and X-ray diffraction (XRD). Samples used in this study are grown by hydride vapor phase epitaxy (HVPE) and have the layer thickness of 0.76, 2.6, 5.3 and 48 m. The PL and PR spectra showed the redshift of the transition energies with increasing layer thickness. This is attributed to strain-induced energy shift. The layer thickness dependence of strains is directly observed by XRD. The strain along the c -axis (εzz) decreased with increasing layer thickness. This indicates the strain is relaxed with layer thickness. From strain variation with layer thickness, we suggest that strain relaxation process is rapid at the initial stage of growth and becomes slower as the layer grows. The full width at half maximum (FWHM) of PL spectra and theta rocking curves decrease with increasing layer thickness. This indicates the crystal quality improves as the strain is reduced. Since the strain effect is very small at the layer thickness of 48 μm, we expect zero strain for thicker layers that can potentially be used as substrates for homoepitaxy.

Studies of Cr-52 resonance parameters by filtered neutron average energy shift method

2009 ◽  
Vol 24 (0) ◽  
pp. 78-84
Author(s):  
О. О. Грицай ◽  
А. К. Гримало ◽  
В. В. Колотий
Keyword(s):  
Average Energy ◽  
Energy Shift ◽  
Shift Method ◽  
Resonance Parameters

Structure and Orientation of As Precipitates in LT-MBE Grown GaAs

1991 ◽  
Vol 49 ◽  
pp. 900-901 ◽  
Author(s):  
Alain Claverie ◽  
Zuzanna Liliental-Weber
Keyword(s):  
Transport Properties ◽  
Layer Thickness ◽  
Growth Temperature ◽  
Low Temperatures ◽  
Lattice Parameter ◽  
Crystalline Quality ◽  
Insulating Properties ◽  
Lt Gaas

GaAs layers grown by MBE at low temperatures (in the 200°C range, LT-GaAs) have been reported to have very interesting electronic and transport properties. Previous studies have shown that, before annealing, the crystalline quality of the layers is related to the growth temperature. Lowering the temperature or increasing the layer thickness generally results in some columnar polycrystalline growth. For the best “temperature-thickness” combinations, the layers may be very As rich (up to 1.25%) resulting in an up to 0.15% increase of the lattice parameter, consistent with the excess As. Only after annealing are the technologically important semi-insulating properties of these layers observed. When annealed in As atmosphere at about 600°C a decrease of the lattice parameter to the substrate value is observed. TEM studies show formation of precipitates which are supposed to be As related since the average As concentration remains almost unchanged upon annealing.

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