Department of Physics

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Subject: search.filters.subject.Atomic force microscope (AFM)

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Now showing 1 - 4 of 4
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    Surface Structure Of Ale-grown Polycrystalline Calcium Sulfide Thin Films Studied By Afm
    (Materials Research Society of Korea, 1998) Dey, Srijata
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    AFM studies of polycrystalline calcium sulfide thin films grown by atomic layer deposition
    (Elsevier, 1999-04) Dey, Srijata
    Polycrystalline CaS thin films were grown on Al2O3 films deposited on Si-wafer using the atomic layer deposition (ALD) technique. The surface structure of these films was studied by AFM and compared with respective SEM images. The polycrystalline film surfaces comprise regular shaped crystallites. First report of a possible growth mechanism is presented, on studying the variation of morphological features (i.e., roughness and size of crystallites) with thickness and growth rate.
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    AFM studies on Langmuir-Blodgett films of cholesterol
    (Springer, 2004) Gupta, Raj Kumar
    The Langmuir monolayer of cholesterol at the air-water interface exhibits a condensed phase in which the cholesterol molecules are aligned normal to the water surface. We have transferred the monolayer from water surface to different substrates by Langmuir-Blodgett (LB) technique and have studied their assembly by atomic force microscope (AFM). Our studies reveal that the aggregation of cholesterol molecules on hydrophobic surfaces leads to interesting structures. The cholesterol molecules assemble into a uniform film, elongated domains and uniformly distributed torus-shaped domains (doughnuts) for one, two and four cycles of deposition, respectively. Beyond four cycles, the molecules adsorb and desorb by an equal amount resulting in no further deposition. The formation of uniformly distributed doughnuts can be attributed to the hydrophobic interaction and reorganization of the molecules due to successive adsorption and desorption during deposition cycles. Our studies on hydrophilic surfaces show that cholesterol cannot form more than one layer of deposition.
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    Studies on morphology of Langmuir-Blodgett films of stearic acid deposited with different orientation of substrates with respect to compression
    (AIP, 2016-05) Gupta, Raj Kumar; Manjuladevi, V.
    The Langmuir monolayer at an air-water interface shows remarkably different surface pressure – area isotherm, when measured with the surface normal of a Wilhemly plate parallel or perpendicular to the direction of compression of the monolayer. Such difference arises due to difference in stress exerted by the monolayer on the plate in different direction. In this article, we report the effect of changing the direction of substrate normal with respect to the compression of the monolayer during Langmuir-Blodgett (LB) film deposition on the morphology of the films. The morphology of the LB film of stearic acid was studied using an atomic force microscope (AFM). The morphology of the LB films was found to be different due to difference in the stress in different directions