Elimination of Basal Plane Dislocations in Epitaxial 4H-SiC via Multicycle Rapid Thermal Annealing

Elimination of basal plane dislocations (BPDs) in epitaxial 4H-SiC is demonstrated via a novel pulsed annealing technique in a moderate N2overpressure of 0.55 MPa. BPD removal in 15 µm thick epitaxial 4H-SiC was confirmed using ultraviolet photoluminescence (UVPL) imaging before and after the annealing process. The samples were capped with a carbon cap, introduced into the annealing chamber, and brought up to a base temperature (TBASE) of around 1550 °C for the pulsed anneal. The multicycle rapid thermal anneal (MRTA) was then performed in the TBASE:TMAXrange, where TMAX= 1875 °C was the peak temperature reached by the annealing cycles. Post-anneal surface quality and carrier lifetime were characterized by atomic force microscopy and time-resolved photoluminescence decay.

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Влияние условий роста и уровня легирования на кинетику люминесценции слоев Ge : Sb, выращенных на кремнии

Физика и техника полупроводников ◽

10.21883/ftp.2020.07.49511.9379 ◽

2020 ◽

Vol 54 (7) ◽

pp. 685

Author(s):

Д.В. Юрасов ◽

Н.А. Байдакова ◽

А.Н. Яблонский ◽

А.В. Новиков

Keyword(s):

Doping Level ◽

Room Temperature ◽

Carrier Lifetime ◽

Growth Conditions ◽

Published Data ◽

Rapid Thermal Anneal ◽

Time Resolved ◽

Light Emitting ◽

Pl Intensity ◽

Time Resolved Photoluminescence

Light-emitting properties of Ge-on-Si(001) layers doped by Sb were studied by stationary and time-resolved photoluminescence (PL) at room temperature. It was obtained that the PL intensity of n-Ge/Si(001) structures is maximized when the doping level is close to the equilibrium solubility of Sb in Ge (~1019 cm-3) which is in accordance with the previously published data. Time-resolved studies of the direct-related PL signal have shown that both the donor density and the growth conditions of doped layer, in particular, the growth temperature influence the PL kinetics. It was obtained that the increase of doping level leads to the decrease of the characteristic carrier lifetime. Moreover, usage of low growth temperatures which is needed to form the doped n-Ge layers also results in shortening of the carrier lifetime as compared with Ge layers grown at high temperatures. It was found that rapid thermal anneal at proper conditions could partially compensate the above mentioned detrimental effects and lead to the increase of both the PL intensity and carrier lifetime.

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Preparation and Time Resolved Photoluminescence of Nanoscale InP Islands in In0.48Ga0.52P

MRS Proceedings ◽

10.1557/proc-379-185 ◽

1995 ◽

Vol 379 ◽

Cited By ~ 3

Author(s):

K. Eberl ◽

A. Kurtenbach ◽

K. HÄusler ◽

F. Noll ◽

W.W. RÜhle

Keyword(s):

Lattice Mismatch ◽

Excitation Power ◽

Buffer Layers ◽

Time Resolved ◽

Force Microscopy ◽

Self Assembling ◽

Atomic Force ◽

Transmission Electron ◽

Decay Times ◽

Time Resolved Photoluminescence

ABSTRACTNanoscale InP islands are formed during InP/In0 48Ga0.52P heteroepitaxy due to the lattice mismatch of about 3.7%. The samples are prepared by solid source molecular beam epitaxy on (001) GaAs substrate. Atomic force microscopy measurements show that the size of the islands is typically 15 to 50 nm in diameter and about 5 to 10 nm high depending on the nominally deposited InP layer thickness, which is between 1 and 7.5 monolayers. Transmission electron micrographs show the coherent incorporation into the In0.48Ga0.52P matrix for InP islands with 2.5 monolayers. Resonantly excited time-resolved photoluminescence (PL) measurements of the self assembling InP dots are performed for optical characterisation. The decay times are typically 400 ps. The dependence on excitation power and temperature indicates the quantum dot nature of the InP islands. Finally a pronounced alignment of the InP islands is obtained on strained In0.61Ga0.39P buffer layers.

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Morphology and Optical Properties of ZnO Nanorods Grown by Catalyst-assisted Vapor Transport on Various Substrates

MRS Proceedings ◽

10.1557/proc-0963-q15-20 ◽

2006 ◽

Vol 963 ◽

Cited By ~ 1

Author(s):

Vitaliy Avrutin ◽

Umit Ozgur ◽

Natalia Izyumskaya ◽

Serguei Chevtchenko ◽

Jacob Leach ◽

...

Keyword(s):

Optical Properties ◽

Substrate Surface ◽

Zno Nanorods ◽

Stimulated Emission ◽

Conductive Atomic Force Microscopy ◽

Vapor Phase Transport ◽

Time Resolved ◽

Force Microscopy ◽

Atomic Force ◽

Time Resolved Photoluminescence

ABSTRACTZnO nanorods were grown by catalyst-assisted vapor phase transport on Si(001), GaN(0001)/c-Al2O3, and bulk ZnO(0001) substrates. Morphology studies showed that ZnO nanorods grew mostly perpendicularly to the GaN substrate surface, whereas a more random directional distribution was found for nanorods on Si. Optical properties of fabricated nanorods were studied by steady-state photoluminescence and time-resolved photoluminescence. Stimulated emission was observed from ZnO nanorods on GaN substrates. Raman spectroscopy revealed biaxial strain in the nanorod samples grown on Si. Conductive atomic force microscopy was applied to study I-V spectra of individual nanorods.

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Surface roughness measurements of vanadium-contaminated fluidized cracking catalysts by atomic force microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166798 ◽

1996 ◽

Vol 54 ◽

pp. 866-867

Author(s):

H. Kinney ◽

M.L. Occelli ◽

S.A.C. Gould

Keyword(s):

Surface Roughness ◽

Zeolite Y ◽

Atomic Level ◽

Microporous Structure ◽

Contact Mode ◽

Force Microscopy ◽

Atomic Force ◽

Before And After ◽

Roughness Measurements ◽

Cracking Catalysts

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.

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Review of time-resolved non-contact electrostatic force microscopy techniques with applications to ionic transport measurements

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.62 ◽

2019 ◽

Vol 10 ◽

pp. 617-633 ◽

Cited By ~ 5

Author(s):

Aaron Mascaro ◽

Yoichi Miyahara ◽

Tyler Enright ◽

Omur E Dagdeviren ◽

Peter Grütter

Keyword(s):

Atomic Force Microscopy ◽

Electrostatic Force ◽

Oscillation Period ◽

Electrostatic Force Microscopy ◽

Time Varying ◽

Time Resolved ◽

Battery Materials ◽

Force Microscopy ◽

Atomic Force ◽

Microscopy Techniques

Recently, there have been a number of variations of electrostatic force microscopy (EFM) that allow for the measurement of time-varying forces arising from phenomena such as ion transport in battery materials or charge separation in photovoltaic systems. These forces reveal information about dynamic processes happening over nanometer length scales due to the nanometer-sized probe tips used in atomic force microscopy. Here, we review in detail several time-resolved EFM techniques based on non-contact atomic force microscopy, elaborating on their specific limitations and challenges. We also introduce a new experimental technique that can resolve time-varying signals well below the oscillation period of the cantilever and compare and contrast it with those previously established.

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The Physicochemical and Antibacterial Properties of Chitosan-Based Materials Modified with Phenolic Acids Irradiated by UVC Light

International Journal of Molecular Sciences ◽

10.3390/ijms22126472 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6472

Author(s):

Beata Kaczmarek-Szczepańska ◽

Marcin Wekwejt ◽

Olha Mazur ◽

Lidia Zasada ◽

Anna Pałubicka ◽

...

Keyword(s):

Thin Films ◽

Antimicrobial Activity ◽

Ferulic Acid ◽

Phenolic Acid ◽

Food Packaging ◽

Antibacterial Properties ◽

Force Microscopy ◽

Atomic Force ◽

Before And After

This paper concerns the physicochemical properties of chitosan/phenolic acid thin films irradiated by ultraviolet radiation with wavelengths between 200 and 290 nm (UVC) light. We investigated the preparation and characterization of thin films based on chitosan (CTS) with tannic (TA), caffeic (CA) and ferulic acid (FA) addition as potential food-packaging materials. Such materials were then exposed to the UVC light (254 nm) for 1 and 2 h to perform the sterilization process. Different properties of thin films before and after irradiation were determined by various methods such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimeter (DSC), mechanical properties and by the surface free energy determination. Moreover, the antimicrobial activity of the films and their potential to reduce the risk of contamination was assessed. The results showed that the phenolic acid improving properties of chitosan-based films, short UVC radiation may be used as sterilization method for those films, and also that the addition of ferulic acid obtains effective antimicrobial activity, which have great benefit for food packing applications.

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Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

Powder Diffraction ◽

10.1017/s0885715613000109 ◽

2013 ◽

Vol 28 (2) ◽

pp. 68-71 ◽

Cited By ~ 40

Author(s):

Thomas N. Blanton ◽

Debasis Majumdar

Keyword(s):

Atomic Force Microscopy ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

High Energy ◽

X Ray Diffraction ◽

Carbon Phase ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

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Фотофизические свойства тонких пленок перилена, модифицированного функциональными группами диангидрида и диимида тетракарбоновой кислоты

Физика твердого тела ◽

10.21883/ftt.2021.09.51281.091 ◽

2021 ◽

Vol 63 (9) ◽

pp. 1437

Author(s):

А.С. Комолов ◽

Э.Ф. Лазнева ◽

Е.В. Жижин ◽

Э.К. Алиджанов ◽

Ю.Д. Лантух ◽

...

Keyword(s):

Charge Carrier ◽

Band Gap ◽

Charge Carrier Mobility ◽

Dark Conductivity ◽

Localized States ◽

Semiconductor Films ◽

Force Microscopy ◽

Atomic Force ◽

Before And After ◽

Carrier Traps

The morphology of organic semiconductor films of perylenetetracarboxylic acid dianhydride (PTCDA) and perylenetetracarboxylic acid dibenzyl-diimide (N, N`-DBPTCDI) formed by thermal vacuum deposition was studied by atomic force microscopy. It was shown that annealing of films at 420 K leads to rearrangement of their structure and crystallization. The optical absorption spectra of the films under study were used to estimate the optical band gap. The temperature dependence of the dark conductivity of PTCDA and N, N-DBPTCDI films before and after annealing (Т = 420 K) was established. The values of the activation energy of charge carrier traps are determined. The computer simulation of the density of localized states in the band gap of the films studied was carried out using the photoconductivity spectra in the constant photocurrent mode. Model photovoltaic cells based on PTCDA / СuPc and N, N-DBPTCDI / СuPc structures were formed. The kinetics of decay of the interfacial photo-voltage of the cells prepared was measured using pulsed light as an excitation source. On the basis of the performed measurements, the charge carrier mobility values in the investigated semiconductor materials were estimated.

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