scholarly journals Dielectric properties of organic monolayers directly bonded on silicon probed by current sensing atomic force microscope

2003 ◽  
Vol 83 (10) ◽  
pp. 2034-2036 ◽  
Author(s):  
Jianwei Zhao ◽  
Kohei Uosaki
2009 ◽  
Vol 9 (9) ◽  
pp. 5467-5470
Author(s):  
Minakshi Chaudhary ◽  
Shirshendu Dey ◽  
Kalyani Date ◽  
S. B. Iyyer ◽  
C. V. Dharmadhikari

2020 ◽  
Vol 17 (Issue 1) ◽  
pp. 62-69
Author(s):  
Arup Sarkar ◽  
K. A. Suresh

To realise the miniaturised devices, the precise measurement of nanoscale tunnelling current in ultrathin films is of utmost importance. For the nanoscale current measurements, current sensing atomic force microscope (CSAFM) is one of the most powerful tool. CSAFM allows to map the current distribution on the film surface and it permits to perform current measurements as a function of applied bias voltage. It has turned out to be crucial for studies of organic films. In CSAFM, a physical contact is made on film with a precise control of the applied force in nanonewton (nN) range. For the preparation of ultrathin film, Langmuir-Blodgett (LB) technique is known to provide a uniform film with a good control over the thickness in the molecular level. In the last two decades, there have been many CSAFM studies for the tunnelling current measurements. This review is intended to cover the literature on the tunnelling current measurements using CSAFM.


Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.


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