scholarly journals Spatially resolved low-frequency noise measured by atomic force microscopy

2009 ◽  
Vol 79 (12) ◽  
Author(s):  
Lynda Cockins ◽  
Yoichi Miyahara ◽  
Peter Grutter
Keyword(s):  
Atomic Force Microscopy ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force

Spatially resolved electrical measurements of SiO2 gate oxides using atomic force microscopy

1993 ◽  
Vol 62 (7) ◽  
pp. 786-788 ◽  
Author(s):  
M. P. Murrell ◽  
M. E. Welland ◽  
S. J. O’Shea ◽  
T. M. H. Wong ◽  
J. R. Barnes ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electrical Measurements ◽  
Gate Oxides ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force

scholarly journals Investigation of the Morphology and Electrical Properties of Graphene Used in the Development of Biosensors for Detection of Influenza Viruses

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Natalia M. Shmidt ◽  
Alexander S. Usikov ◽  
Evgeniia I. Shabunina ◽  
Alexey V. Nashchekin ◽  
Ekaterina V. Gushchina ◽  
...  
Keyword(s):  
Low Frequency ◽  
Influenza Viruses ◽  
Virus Concentration ◽  
Frequency Noise ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Films ◽  
Response Versus ◽  
Phosphate Buffered Saline ◽  
Biosensor Response

In this study, we discuss the mechanisms behind changes in the conductivity, low-frequency noise, and surface morphology of biosensor chips based on graphene films on SiC substrates during the main stages of the creation of biosensors for detecting influenza viruses. The formation of phenylamine groups and a change in graphene nano-arrangement during functionalization causes an increase in defectiveness and conductivity. Functionalization leads to the formation of large hexagonal honeycomb-like defects up to 500 nm, the concentration of which is affected by the number of bilayer or multilayer inclusions in graphene. The chips fabricated allowed us to detect the influenza viruses in a concentration range of 10−16 g/mL to 10−10 g/mL in PBS (phosphate buffered saline). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed that these defects are responsible for the inhomogeneous aggregation of antibodies and influenza viruses over the functionalized graphene surface. Non-uniform aggregation is responsible for a weak non-linear logarithmic dependence of the biosensor response versus the virus concentration in PBS. This feature of graphene nano-arrangement affects the reliability of detection of extremely low virus concentrations at the early stages of disease.

Frequency noise in frequency modulation atomic force microscopy

2009 ◽  
Vol 80 (4) ◽  
pp. 043708 ◽  
Author(s):  
Kei Kobayashi ◽  
Hirofumi Yamada ◽  
Kazumi Matsushige
Keyword(s):  
Atomic Force Microscopy ◽  
Frequency Modulation ◽  
Frequency Noise ◽  
Force Microscopy ◽  
Atomic Force

Spatially resolved organic coating on clay minerals in bitumen froth revealed by atomic force microscopy adhesion mapping

Fuel ◽  
2017 ◽  
Vol 191 ◽  
pp. 283-289 ◽  
Author(s):  
Qiang Chen ◽  
Jun Liu ◽  
Thomas Thundat ◽  
Murray R. Gray ◽  
Qi Liu
Keyword(s):  
Atomic Force Microscopy ◽  
Clay Minerals ◽  
Organic Coating ◽  
Force Microscopy ◽  
Spatially Resolved ◽  
Atomic Force

scholarly journals Improved atomic force microscopy cantilever performance by partial reflective coating

2015 ◽  
Vol 6 ◽  
pp. 1450-1456 ◽  
Author(s):  
Zeno Schumacher ◽  
Yoichi Miyahara ◽  
Laure Aeschimann ◽  
Peter Grütter
Keyword(s):  
Atomic Force Microscopy ◽  
High Vacuum ◽  
Low Frequency ◽  
Beam Deflection ◽  
High Signal ◽  
Dynamic Mode ◽  
Contact Mode ◽  
Force Microscopy ◽  
Reflective Coating ◽  
Atomic Force

Optical beam deflection systems are widely used in cantilever based atomic force microscopy (AFM). Most commercial cantilevers have a reflective metal coating on the detector side to increase the reflectivity in order to achieve a high signal on the photodiode. Although the reflective coating is usually much thinner than the cantilever, it can still significantly contribute to the damping of the cantilever, leading to a lower mechanical quality factor (Q-factor). In dynamic mode operation in high vacuum, a cantilever with a high Q-factor is desired in order to achieve a lower minimal detectable force. The reflective coating can also increase the low-frequency force noise. In contact mode and force spectroscopy, a cantilever with minimal low-frequency force noise is desirable. We present a study on cantilevers with a partial reflective coating on the detector side. For this study, soft (≈0.01 N/m) and stiff (≈28 N/m) rectangular cantilevers were used with a custom partial coating at the tip end of the cantilever. The Q-factor, the detection and the force noise of fully coated, partially coated and uncoated cantilevers are compared and force distance curves are shown. Our results show an improvement in low-frequency force noise and increased Q-factor for the partially coated cantilevers compared to fully coated ones while maintaining the same reflectivity, therefore making it possible to combine the best of both worlds.

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