CVD Growth and Excimer Laser Processing of SiGe Alloys Monitored by Single Wavelength Ellipsometry and Atomic Force Microscopy

1997 ◽  
Vol 502 ◽  
Author(s):  
R. Larciprete ◽  
G. Padeletti ◽  
S. Cozzi ◽  
S. Pieretti
Keyword(s):  
Atomic Force Microscopy ◽  
Laser Processing ◽  
Growth Parameters ◽  
Laser Pulses ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Analysis ◽  
Cvd Growth ◽  
Sample Irradiation

ABSTRACTSingle wavelength ellipsometry was used to monitor the CVD growth of Si(1-x)Gex alloys onSi and to evaluate the effect of sample irradiation by KrF laser pulses, performed during or afterthe CVD growth. The information obtained was correlated with AFM analysis results in order tooptimize the growth parameters for an improved morphological quality of the alloy layers.

scholarly journals A Simple Approach for the Synthesis of Gold Nanoparticles Mediated by Layered Double Hydroxide

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Aires da Conceição Silva ◽  
Andréa Luzia Ferreira de Souza ◽  
Renata Antoun Simão ◽  
Luiz Fernando Brum Malta
Keyword(s):  
Gold Nanoparticles ◽  
Atomic Force Microscopy ◽  
Layered Double Hydroxide ◽  
Xrd Analysis ◽  
Reducing Agents ◽  
Simple Approach ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Analysis ◽  
Double Hydroxide

The present work introduces a new procedure to obtain gold nanoparticles (AuNPs). AuNPs (77–213 nm) were obtained in the absence of any classical reducing agents in a medium containing Mg2+/Al3+layered double hydroxide (LDH) andN,N-dimethylformamide. XRD analysis showed the presence of crystalline phases of gold in the Au/LDH composite. The 2θvalues of peaks corresponding to the LDH interlayer distance indicated that metallic NPs were deposited on the surface of the material. Furthermore, atomic force microscopy (AFM) analysis showed that AuNPs tend to agglomerate in a nonclassical halter-like shape.

Growth of GaN epilayers on Si(111) substrates using multiple buffer layers

2001 ◽  
Vol 693 ◽  
Author(s):  
P.R. Hageman ◽  
S. Haffouz ◽  
A. Grzegorczk ◽  
V. Kirilyuk ◽  
P.K. Larsen
Keyword(s):  
Atomic Force Microscopy ◽  
Epitaxial Films ◽  
Buffer Layers ◽  
High Quality ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Vapor Deposition Technique

AbstractWe present a study of the growth of high quality GaN films on Si(111) substrates by MetalOrganic Chemical Vapor Deposition technique. In order to improve the quality of the epitaxial films we introduced different nucleation or buffer layers and combinations of them. Our results obtained on an optimized AlN nucleation layer will serve as reference point. In order to improve the quality of the epitaxial films we introduced different combinations of nucleation and intermediate layers. The first combination consists of an optimized AlN nucleation layer followed by a 1 m-thick GaN film, on which we deposited SixNy/GaN intermediate layers. Based on the optimized AlN nucleation layer, we introduced AlGaN/GaN superlattices or AlN intermediate buffer layers. Additionally, we present results on the modification the Si(111) surface with NH3 to promote nucleation from selective GaN islands. In all experiments the total thickness of the GaN epilayers was 3 m m. X-ray diffraction, photoluminescence, Hall measurements and atomic force microscopy were used in order to elucidate the effectiveness of these growth processes. For the most successful deposition scheme, the one with the SixNy/GaN intermediate layers, the resulting GaN layers are of high quality as compared to the other methods. The donor bound exciton, which dominates the photoluminescence spectrum, showed a full width at half maximum (FWHM) of about 50 meV at room temperature and 10 meV at 4K. The FWHM of the symmetric (0002) rocking curves in w-scan is about 640 arcsec. The root-mean-square roughness, as measured by atomic force microscopy, does not exceed 10 Å.

Femtosecond Laser Micromachining of Periodical Structures in Si

2004 ◽  
Vol 850 ◽  
Author(s):  
Mohamed El-Bandrawy ◽  
Mool C. Gupta
Keyword(s):  
Laser Pulses ◽  
Light Polarization ◽  
Objective Lens ◽  
Force Microscopy ◽  
Laser Parameters ◽  
Femtosecond Laser Micromachining ◽  
Atomic Force ◽  
Fs Laser ◽  
Polarization Orientation

ABSTRACTA frequency doubled femtosecond Ti: sapphire laser at a wavelength of 400 nm, a pulse width of 160 fs, and a repetition rate of 1 kHz was used with a computer controlled galvo head to write periodical structures in Si <100>. Laser pulses of ∼130 nJ were focused using an objective lens of 0.65 NA. Laser parameters were optimized for efficient submicron ablation, yielding 700 nm wide by 600 nm deep lines. 1-D and 2-D periodical structures of 5 and 5x5 micron periods, respectively, were fabricated and examined using optical and atomic force microscopy. The quality of the 1-D and 2-D structures was highly depended on the light polarization orientation with respect to micromachining direction. With optimized fs laser parameters, high quality 1-D and 2-D periodical structures were obtained, which would have applications in optical devices.

scholarly journals AFM ANALYSIS OF ENAMEL DAMAGE DUE TO ETCHING WITH ORTHOPHOSPHORIC ACID

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Vladan Mirjanić ◽  
Đorđe Mirjanić
Keyword(s):  
Atomic Force Microscopy ◽  
Orthophosphoric Acid ◽  
Tooth Enamel ◽  
Modern Technology ◽  
Single Plane ◽  
Force Microscopy ◽  
Atomic Force ◽  
Precise Analysis ◽  
Afm Analysis ◽  
Scientific Fields

Bearing in mind that in the field of jaw orthopedics and related scientific fields, there are no scientific studies that use the most modern technology based on the Atomic Force Microscopy (AFM) to investigate the nanostructure of tooth enamel after etching with 37% orthophosphoric acid, in this paper we will use this method, which is currently the most reliable, to determine the degree of tooth damage after its etching in the process of fixing orthodontic brackets. Considering the fact that the degree of enamel damage after etching cannot be realistically comprehended by the method called ’network’, because in this way the damage cannot be seen three dimensionally (the depth of the damage), but only the damage in a single plane, a more precise analysis can be obtained with the application of the most contemporary method that we can apply in this case, and that is the application of AFM technology.

IMPROVED CHEMICAL SYNTHESIS OF GRAPHENE USING A SAFER SOLVOTHERMAL ROUTE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 39-42 ◽  
Author(s):  
DILIP KUMAR SINGH ◽  
P. K. IYER ◽  
P. K. GIRI
Keyword(s):  
Electron Microscopy ◽  
Graphene Sheets ◽  
Pyrolysis Process ◽  
High Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Analysis ◽  
Bulk Production

Graphene has been synthesized using thermal decomposition of ethyl alcohol in a medium pressure autoclave. The synthesis was carried out in the presence of strong alkaline solution at a temperature of ~230°C and pressure of 60 bar. The as-synthesized graphene has been characterized using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). AFM analysis on various graphene sheets shows the presence of monolayer (n = 1) to trilayer (n = 3) graphene sheets with thickness of ~1.168 nm. HRTEM studies confirm the high quality of graphene obtained after purification of as-synthesized product. Use of chemically nonexplosive material for synthesis and reduced reaction time along with the absence of post-pyrolysis process make it a commercially viable process for bulk production of graphene.

Sign in / Sign up

Export Citation Format

Share Document