Temperature-dependent evolution of the wetting layer thickness during Ge deposition on Si(001)

2011 ◽  
Vol 22 (28) ◽  
pp. 285704 ◽  
Author(s):  
R Bergamaschini ◽  
M Brehm ◽  
M Grydlik ◽  
T Fromherz ◽  
G Bauer ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Wetting Layer ◽  
Temperature Dependent

Stranski-Krastanov growth for InGaN/GaN: wetting layer thickness changes

2005 ◽  
pp. 13-16
Author(s):  
N K van der Laak ◽  
R A Oliver ◽  
M J Kappers ◽  
C McAleese ◽  
C J Humphreys
Keyword(s):  
Layer Thickness ◽  
Wetting Layer

Morphologies of Self-Assembled Quantum Dots: A Variational Approach

2001 ◽  
Vol 707 ◽  
Author(s):  
R. Arief Budiman ◽  
Harry E. Ruda
Keyword(s):  
Quantum Dots ◽  
External Field ◽  
Layer Thickness ◽  
Variational Approach ◽  
3D Model ◽  
Strain Tensor ◽  
Wetting Layer ◽  
Strained Layer ◽  
Adatom Diffusion ◽  
Equilibrium Shapes

ABSTRACTWe construct a 3D model for coherent island formation by (i) using a novel 3D strain tensor to account for bulk strains and (ii) representing adatom diffusion as an external field that perturbs an otherwise flat strained layer. Equilibrium shapes of coherent islands and wetting layer thickness are obtained. Coherently compressed layers are typically unstable, but become stable in tension. Comparisons with Si1-xGex/Si(001) and Si0.5Ge0.5/Si1-xGex(001) layers are discussed.

On the free energy of nematic wetting layers

1988 ◽  
Vol 66 (4) ◽  
pp. 553-556 ◽  
Author(s):  
Donald E. Sullivan ◽  
Reinhard Lipowsky
Keyword(s):  
Free Energy ◽  
Layer Thickness ◽  
Order Parameter ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Wetting Layer ◽  
Nematic Director ◽  
The Mean ◽  
Wetting Layers

The contributions to the free energy of a nematic wetting layer as a function of its thickness l are analyzed. The longest-range contribution is due to distortion of the nematic director across the film, resulting from different preferred molecular orientations at the two interfaces bounding the film. Van der Waals forces as well as the decaying tails of the interfacial order-parameter profiles yield contributions to the free energy of successively shorter range. These effects lead to crossovers between different scaling régimes for variation of the mean wetting-layer thickness with temperature. Experimental implications of the results are described.

Effects of a InGaAs Strained Layer on Structures and Photoluminescence Characteristics of InAs Quantum Dots

2010 ◽  
Vol 148-149 ◽  
pp. 897-902
Author(s):  
Jian Ming Yao ◽  
Ling Min Kong ◽  
Shi Lai Wang
Keyword(s):  
Quantum Dots ◽  
Integral Intensity ◽  
Wetting Layer ◽  
Ingaas Layer ◽  
Temperature Dependent ◽  
Inas Quantum Dots ◽  
Strained Layer ◽  
Gaas Matrix ◽  
Electronic Microscope ◽  
Temperature Dependent Photoluminescence

The influences of a thin InGaAs layer grown on GaAs(100) substrate before deposited InAs self-assembled quantum dots(SAQDs) were experimentally investigated. Scanning electronic microscope (SEM) measurements show that the InGaAs strained layer may release the strain between wetting layer and QDs, and then enlarge size of QDs. When the thickness of InAs layer is small, the QDs are chained. Temperature dependent photoluminescence (TDPL) measurements show that the PL peaks of InAs QDs with In0.1Ga0.9As show much more red shift compared with the QDs directly deposited on GaAs matrix, and PL integral intensity enhances as T rises from 50K to 90K. We attribute this enhancement to the small potential barrier between WL and QDs produced by the InGaAs stained layer.

Temperature and humidity effects on the stability of on-plastic a-Si:H thin film transistors with various conduction channel layer thicknesses

2008 ◽  
Vol 1066 ◽  
Author(s):  
Jian Z Chen ◽  
I-Chun Cheng
Keyword(s):  
Layer Thickness ◽  
Temperature Dependent ◽  
Current Ratio ◽  
Humidity Effects ◽  
Channel Layer ◽  
Humidity Change ◽  
Conduction Channel ◽  
Order Of Magnitude ◽  
The Stability ◽  
Conduction Layer

ABSTRACTStability is an important issue for the application of TFTs. In this paper, we present the effects of humidity and temperature on the stability of inverted-staggered back-channel-cut a-Si:H TFTs with various conduction channel layer thickness. We evaluated the stability of on-plastic TFTs of different conduction layer thicknesses made at a process temperature of 150°C on 51-μm thick Kapton polyimide foil substrates.. With conduction channel layer thickness of 50nm, humidity reversibly varies the characteristics of TFTs, but TFTs of conduction layer thickness greater than 100 nm is pretty immune to the humidity change. The temperature dependent stability and characteristics of TFTs were analyzed from 20°C to 60°C. Rising temperature from 20°C to 56°C, the threshold voltage (Vt) drops about 2 volts; on-off current ratio decreases by one order of magnitude mainly due to thermally excited carriers in the off-region.

Temperature and Active Layer Thickness Dependent Stability of On-Plastic a-Si:H Thin Film Transistors Fabricated at 150°C

2008 ◽  
Author(s):  
Jian-Zhang Chen ◽  
I-Chun Cheng
Keyword(s):  
Layer Thickness ◽  
Active Layer ◽  
Thin Film Transistors ◽  
Active Layer Thickness ◽  
Temperature Dependent ◽  
Current Ratio ◽  
Humidity Change ◽  
Order Of Magnitude ◽  
Polyimide Foil ◽  
The Stability

Stability is an important issue for the application of TFTs. In this paper, we present the effects temperature, and humidity on the stability of inverted-staggered back-channel-cut a-Si:H TFTs of various active layer thicknesses. The amorphous TFTs were made at a process temperature of 150°C on 51-μm thick Kapton polyimide foil substrates. With active layer thickness of 50nm, humidity reversibly varies the characteristics of TFTs, but TFTs of active layer thickness greater than 100 nm is pretty stable to the humidity change, which is attributed to backchannel conduction. The temperature dependent stability and characteristics of 200nm active-layer thickness TFTs were analyzed from 20°C to 60°C. Rising temperature from 20°C to 60°C, the threshold voltage (Vt) drops about 2 volts; on-off current ratio decreases by one order of magnitude mainly due to thermally excited carriers [1].

Raman Scattering Study for Self-Organized Ge Quantum Dots Formed on Si Substrate

2002 ◽  
Vol 744 ◽  
Author(s):  
T. R. Yang ◽  
M. M. Dvoynenko ◽  
Z. C. Feng ◽  
I. Ferguson ◽  
H. H. Cheng
Keyword(s):  
Quantum Dots ◽  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Layer Thickness ◽  
Line Width ◽  
Wetting Layer ◽  
Si Substrate ◽  
Spectroscopy Technique ◽  
Self Organized ◽  
Scattering Study

ABSTRACTA Raman scattering study for self-organized Ge dots on Si substrate is presented. Raman signals from the Ge islands and Si substrate have been separated, by means of difference Raman spectroscopy technique. The wetting layer thickness and strain were estimated from the line width and the position of the peak. The estimated wetting layer thickness values are comparative with the Ge dot height obtained from microscopy measurements. As explained, the strain is observed to decrease with an increase of the Ge island height and the wetting layer thickness.

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