Thermally activated diffusion of impurities along a semiconductor layer

2022 ◽  
Vol 95 (1) ◽  
Author(s):  
Yoseph Abebe ◽  
Tibebe Birhanu ◽  
Lemi Demeyu ◽  
Mesfin Taye ◽  
Mulugeta Bekele ◽  
...  
Keyword(s):  
Semiconductor Layer ◽  
Thermally Activated ◽  
Diffusion Of Impurities

Stochastic resonance of charge carrier diffusion in a nonhomogeneous medium in the presence of an harmonic external potential

2014 ◽  
Vol 28 (29) ◽  
pp. 1550011 ◽  
Author(s):  
Berhanu Aragie
Keyword(s):  
Stochastic Resonance ◽  
Charge Carriers ◽  
Semiconductor Layer ◽  
Model Parameters ◽  
Nonhomogeneous Medium ◽  
Potential Minimum ◽  
Thermally Activated ◽  
Charge Carrier Diffusion ◽  
Lower Temperature ◽  
And Diffusion

The dynamics of charge carriers (electrons) hopping through a nonhomogeneous medium in semiconductor layer is investigated by changing a thermal noise of strength D and an external harmonic potential V(x). The nonhomogeneous medium exhibits denser trap distribution around the center, which biases the electrons to therein concentrate. Applying also a monostable potential at the center further enhances the accumulation of electrons. However, by applying a nonhomogeneous hot temperature in the vicinity of the potential minimum forced the electrons to diffuse away from the center and redistribute around two points. Thermally activated rate of hopping and diffusion of electrons in a nonhomogeneous medium, as a function of model parameters, is also considered in the high barrier limit. Using two states approximation, I have also studied the stochastic resonance (SR) of the electrons dynamics in the presence of a time-varying signal. I found a strong spectral amplification η and lower temperature occurrence of its peak as compared to previous works [M. Asfaw, B. Aragie and M. Bekele, Eur. Phys. J. B 79, 371 (2011); B. Aragie, Y. B. Tateka and M. Bekele, Eur. Phys. J. B 87, 101 (2014)].

UHV-TEM studies of laser-induced damage

1991 ◽  
Vol 49 ◽  
pp. 632-633
Author(s):  
T.S. Savage ◽  
R. Ai ◽  
D. Dunn ◽  
L.D. Marks
Keyword(s):  
Surface Science ◽  
Rapid Heating ◽  
Local Heating ◽  
Routine Practice ◽  
Transmission Electron ◽  
Northwestern University ◽  
Laser Induced Damage ◽  
Set Up ◽  
Focusing Lens ◽  
Diffusion Of Impurities

The use of lasers for surface annealing, heating and/or damage has become a routine practice in the study of materials. Lasers have been closely looked at as an annealing technique for silicon and other semiconductors. They allow for local heating from a beam which can be focused and tuned to different wavelengths for specific tasks. Pulsed dye lasers allow for short, quick bursts which can allow the sample to be rapidly heated and quenched. This short, rapid heating period may be important for cases where diffusion of impurities or dopants may not be desirable.At Northwestern University, a Candela SLL - 250 pulsed dye laser, with a maximum power of 1 Joule/pulse over 350 - 400 nanoseconds, has been set up in conjunction with a Hitachi UHV-H9000 transmission electron microscope. The laser beam is introduced into the surface science chamber through a series of mirrors, a focusing lens and a six inch quartz window.

Thermally activated flow of β-titanium and β-titanium-hydrogen alloys

2000 ◽  
Vol 80 (12) ◽  
pp. 2813-2825
Author(s):  
O. N. Senkov, J. J. Jonas, F. H. Froes
Keyword(s):  
Thermally Activated

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

Mass spectrometric study of allyl radical, allyl bromide and 1,5-hexadiene interactions with oxides; Cobalt suboxide Co3O4

1979 ◽  
Vol 44 (7) ◽  
pp. 2009-2014 ◽  
Author(s):  
Jana Nováková ◽  
Zdeněk Dolejšek
Keyword(s):  
Room Temperature ◽  
Allyl Bromide ◽  
Catalytic Properties ◽  
Mass Spectrometric Study ◽  
Spectrometric Study ◽  
Flow Conditions ◽  
Allyl Radical ◽  
Knudsen Flow ◽  
Thermally Activated ◽  
Radical Interaction

Products of (a) allyl radical interaction with unheated Co3O4, (b) thermally activated 1,5-hexadiene or thermally activated allyl bromide with unheated Co3O4, (c) moderately heated Co3O4 with unheated 1,5-hexadiene or allyl bromide were studied under Knudsen flow conditions. Cobalt suboxide Co3O4, a typical catalyst of deep oxidations yielded acrolein in reaction with allyl radicals as early as at the room temperature of the catalyst. A similar acrolein formation was also observed in the allyl radical interaction with other oxides exhibiting different catalytic properties. It appears that acrolein is in general the primary product of the allyl radical interaction with the oxides. The results are discussed and compared with previous data obtained with MoO3.

Effect of grain size on the vapour phase hydration of monoclinic and triclinic modifications of tricalcium silicate; role of high temperature activation

1991 ◽  
Vol 56 (10) ◽  
pp. 1993-2008
Author(s):  
S. Hanafi ◽  
G. M. S. El-Shafei ◽  
B. Abd El-Hamid
Keyword(s):  
Particle Size ◽  
Vapour Phase ◽  
Tricalcium Silicate ◽  
Active Centers ◽  
Thermally Activated ◽  
Grain Sizes ◽  
Intermediate Size ◽  
Surface Active ◽  
Temperature Activation

The hydration of tricalcium silicate (C3S) with three grain sizes of monoclinic (M) and triclinic (T) modifications and on their thermally activated samples were investigated by exposure to water vapour at 80°C for 60 days. The products were investigated by XRD, TG and N2 adsorption. The smaller the particle size the greater was the hydration for both dried and activated samples from (M). In the activated samples a hydrate with 2θ values of 38.4°, 44.6° and 48.6° could be identified. Hydration increased with particle size for the unactivated (T) samples but after activation the intermediate size exhibited enhanced hydration. Thermal treatment at 950°C of (T) samples increased the surface active centers on the expense of those in the bulk. Changes produced in surface texture upon activation and/or hydration are discussed.

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