scholarly journals Characterisation of InGaN by Photoconductive Atomic Force Microscopy

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1794 ◽  
Author(s):  
Thomas Weatherley ◽  
Fabien Massabuau ◽  
Menno Kappers ◽  
Rachel Oliver

Nanoscale structure has a large effect on the optoelectronic properties of InGaN, a material vital for energy saving technologies such as light emitting diodes. Photoconductive atomic force microscopy (PC-AFM) provides a new way to investigate this effect. In this study, PC-AFM was used to characterise four thick (∼130 nm) In x Ga 1 − x N films with x = 5%, 9%, 12%, and 15%. Lower photocurrent was observed on elevated ridges around defects (such as V-pits) in the films with x ≤ 12 %. Current-voltage curve analysis using the PC-AFM setup showed that this was due to a higher turn-on voltage on these ridges compared to surrounding material. To further understand this phenomenon, V-pit cross sections from the 9% and 15% films were characterised using transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. This identified a subsurface indium-deficient region surrounding the V-pit in the lower indium content film, which was not present in the 15% sample. Although this cannot directly explain the impact of ridges on turn-on voltage, it is likely to be related. Overall, the data presented here demonstrate the potential of PC-AFM in the field of III-nitride semiconductors.

2015 ◽  
Vol 10 (1) ◽  
pp. 155892501501000
Author(s):  
Serpil Koral Koc

Potential applications of atomic force microscopy (AFM) in textiles are explained. For this purpose samples were carefully selected from both natural and synthetic fibers. Cotton, wool, conventional polyethylene terepthalate (PET), antibacterial PET, and antistatic PET were investigated by means of 3D topography imaging, phase imaging, and calculation of their Rq values. The distribution of the additives in the cross sections of antibacterial PET and antistatic PET were analyzed. Moreover, differences between inner and outer cross section of trilobal PET was observed by force spectroscopy. The results are discussed considering the fiber properties. It is concluded that AFM is a powerful tool to investigate different properties of textile fibers, and it gives valuable information.


2020 ◽  
Vol 992 ◽  
pp. 580-584
Author(s):  
V.Yu. Chukhlanov ◽  
O.G. Selivanov ◽  
N.V. Chukhlanova

New materials based on oligooxidridsilmethylensiloxysilane nanostructured with ethyl ester of orthosilicic acid – tetraethoxysilane have been studied in the research. Tetraethoxysilane introduction into the composition is supposed to cause its decomposition up to nanoparticles of silicon oxide. The alkoxysilane hydrolytic destruction kinetics and the impact of the composition and nature of the polymer composition components on the physical properties have been studied. Atomic force microscopy was used to study the structurization kinetics of the polymer composition. The composition hydrophobicity was determined by the edge wetting angle. To study the adhesion characteristics of the obtained material, the method of disc separation from the substrate has been used. The relative rigidity has been determined by a pendulum device M3. Atomic force microscopy revealed the presence of nanoscale neoplasms (at average of one hundred twenty per one square micrometer) in diameter from two to five nanometers in the surface structure of the composition, modified with tetraethoxysilane. Herewith the physical properties of the material change: rigidity increases, the edge angle of wetting increases as well. The studied nanostructured compositions can also be applied. For example – they can be used as a protective coating with a set of special properties, such as high hydrophobicity.


2002 ◽  
Vol 01 (05n06) ◽  
pp. 725-730 ◽  
Author(s):  
M. S. XU ◽  
J. B. XU ◽  
J. AN

Variable temperature tapping mode atomic force microscopy is exploited to in situ visualize the morphological evolution of N, N'-di(naphthalene-1-yl)-N, N'-diphthalbenzidine (NPB) thin film. The apparent glass transition of the NPB thin film initially occurred at 60°C, proceeded until 95°C, and crystallization from the glassy state quickly appeared at 135°C. The NPB thin film gradually melted and disappeared when the temperature was above 175°C, revealing the underlying layer. These observations are technically helpful and significant to gauge the temperature dependent lifetime and luminance of organic light-emitting diodes.


2014 ◽  
Vol 6 (22) ◽  
pp. 8940-8945 ◽  
Author(s):  
Shawn C. Owens ◽  
Jacob A. Berenbeim ◽  
Catherine Schmidt Patterson ◽  
Eoghan P. Dillon ◽  
M. S. de Vries

Cross-sections containing organic dyes are used to demonstrate sub-micron atomic force microscopy thermal desorption (AFM-TD), followed by laser mass spectrometry.


1999 ◽  
Vol 146 (10) ◽  
pp. 3711-3715 ◽  
Author(s):  
F. Echeverria ◽  
P. Skeldon ◽  
G. E. Thompson ◽  
H. Habazaki ◽  
K. Shimizu

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Yong Wu He ◽  
Yi Feng ◽  
Lian Wei Kang ◽  
Xiao Liang Li

A graphene oxide- (GO-) boradiazaindacenes (BODIPY) charge-transfer complex (BGO) has been easily synthesized, and the structure of BGO was confirmed by FT-IR and atomic force microscopy (AFM). Moreover, the BGO was found that could be used as a turn-on fluorescent sensor for Hg2+. Upon addition of Hg2+, the fluorescence of BGO would be enhanced since the energy transfer between BODIPY and GO was inhibited. The selectivity and the competition performance of BGO towards Hg2+ were good among other heavy metal ions.


Sign in / Sign up

Export Citation Format

Share Document