Speckle Interferometric Investigation of Argon Pressure-Induced Surface Roughness Modifications in RF-Sputtered MoO3 Film

Soumya, Surabhi; Kumar, Rohit; Sreejyothi, S.; Raj, Vimal; Swapna, M. S.; Sankararaman, S.

doi:10.1007/s10921-020-00741-x

Cited by 4 publications

(10 citation statements)

References 25 publications

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“…The presence of Argon gas modified the kinetic energy distribution of ablated particles and had a considerable effect on the film's quality. [ 31 ] The chamber base pressure was maintained at 10 −6 mbar, powdered sodium carbide was placed in the sputtering target, and the film deposition was conducted at a background argon pressure of 0.06 mbar. The target was powered by a magnetron (Advanced Energy, MDX 500) operating at 13.56 MHz and 200 W of RF power.…”

Section: Methodsmentioning

confidence: 99%

Divulging the Potential of Sodium Carbide Thin Film for Semiconductor Applications

Swapna

Sankararaman

2023

Physica Status Solidi (b)

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The advancement in semiconductor technology led to the development of novel materials with tailored properties. Besides the widely employed semiconductors like germanium, silicon, gallium arsenide, gallium nitride, gallium phosphide, cadmium sulfide, and composites, recently, the potential of carbide semiconductors has been widely explored to cater for the needs of the electronic industry. [1,2] Semiconducting thin films are extensively used in modern technological applications like plasma screen displays, organic light-emitting diodes, solar cells, and sensors. [2,3] Among the compound semiconductors, carbide-based electronic materials, primarily silicon carbide, are emerging as promising materials for applications demanding high power, fast switching speed, high temperature, better radiation tolerance, and high efficiency. [4,5] The success story of silicon carbide in electronics also tempted researchers to investigate other carbides.Carbides consisting of nonmetallic carbon (C) and metallic/semimetallic elements with lower electronegativity have various industrial uses due to their valuable structural and physical characteristics. [6,7] Although carbides have been used as refractory materials for more than a century, the scientific community is currently very interested in this material due to its use in a variety of scientific and technological disciplines. Carbides have uses in electronics and photonics in addition to the more conventional ones based on their durability and refractoriness. [5,6,[8][9][10] Excellent melting point and high chemical stability are crucial characteristics that define carbides as a refractory material. Covalent and interstitial carbides are found to satisfy these requirements. [6,7,11] Even if intermediate and salt-like carbides do not meet one or both of these requirements, they have industrial uses.Alkali, alkali earth, and group III metals with carbon combine to generate ionic carbides, sometimes referred to as salt-like (saline) carbides having extremely high ionic and electronegativity characteristics. The carbides formed by sodium are-Na 2 C 2 , NaC, NaC 64 , and NaC 2 with carbon atoms in chains, networks, and solitary. [9,12] These carbides have a graphite-like structure with metal atoms sandwiched in between the various layers of carbon atoms. The common type of saline carbide is the sodium carbide (Na 2 C 2 ), also known as disodium acetylide, which is an inert, clear material with no color. However, it quickly decomposes in the presence of acids/water/carbon, forming aliphatic hydrocarbons, which appear black or gray. Each Na þ ion in sodium carbide is surrounded by six C À ions that are in close proximity to it and vice versa. The ideal anti-CaF 2 structure is distorted by the spiral arrangement of the C 2 2À array in the sodium carbide structure. As a result, Na 2 C 2 crystallizes in an anti-CaF 2 structure deformed with a CC distance of 120 pm. The C 2 2À ions in them are loosely packed, which results in a low crystal density of 1.6 g cm À3 . [12,13] Sodium carbide f...

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Section: Methodsmentioning

confidence: 99%

Divulging the Potential of Sodium Carbide Thin Film for Semiconductor Applications

Swapna

Sankararaman

2023

Physica Status Solidi (b)

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“…To delineate the potential of graph-based complex network features in untangling the thermal-induced intrafilm dynamics hidden in the specklegram, a thin film of molybdenum oxide (MoO 3 ) was prepared by RF magnetron sputtering technique. [7,30] The RF sputtering technique was selected because of its potential to produce low-cost, uniform, and good quality films with tailored stoichiometry. [31] The quality of the deposited films depend on various deposition parameters.…”

Section: Methodsmentioning

confidence: 99%

“…From the stylus profilometer, the film thickness was obtained as 150 nm. The thin film preparation by RF sputtering technique and the experimental setup for recording the specklegram were detailed in an earlier work of the author, [7] and the schematic of the experimental setup is , and (45-50 °C), respectively. Thus, 500 frames of the speckle image of pixel size 601 × 601 were extracted from the videograph of each temperature interval using MATLAB.…”

Section: Methodsmentioning

confidence: 99%

“…[1,2] The speckle interferometry, developed by Butter and Leendertz, [3] providing several advantages over holographic interferometry, finds application in metrology, biomedical, aerospace, mechanical, civil, and material engineering. [4][5][6][7][8][9] When a laser is shone on a surface, the scattered light emanating from the microscopic regions of the surface results in a random interference pattern termed laser speckle. The recorded dual-beam interference pattern between the speckle and a reference wave carries the phase information pertaining to the surface.…”

Section: Introductionmentioning

confidence: 99%

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How the Complex Network of Specklegram Deciphers Intra‐Film Thermal Induced Dynamics?

Sankararaman

2021

Annalen der Physik

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The present work deciphers the potential of the graph and its features in the speckle-based nondestructive evaluation of intra film thermal-induced dynamics. The molybdenum oxide film, prepared by sputtering technique, containing nanorods is subjected to thermal stress from 30-50 °C and the specklegrams are recorded. The co-occurrence matrix (CM) and heat map analyses of the specklegrams by dividing the temperature range into four intervals of 5 °C each reveal that the thermal stress drives the film from a less stable to a more stable state from the third to the fourth temperature interval. The CM analysis indicates the thermal-induced rearrangements among the nanorods of the film. By extracting frames from the videograph of the speckle pattern during temperature variation, a complex network is constructed, taking the middle column of each frame as a node. The graph features also become minimum in the third interval and increase in the fourth interval revealing that the film moves to a more ordered state under thermal stress. The analysis of the specklegram by CM, heat map, and graph suggests that graph features present a high sensitivity compared to the other methods.

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“…Thin film technologies have revolutionized electronic and photonic industries enabling the development of micro-electronic and nano-electronic devices. Among thin films, metal-oxide thin films have emerged as an exciting class in terms of their widespread applications in sensors, detectors, solar panels, smart windows, fuel cells, transparent conducting electrodes, thermochromic and photochromics [1,2]. The physical, chemical and optical behaviour of thin film greatly depends on the surface morphology, composition, material, and preparation techniques.…”

Section: Introductionmentioning

confidence: 99%

Reflections of thin film surface roughness on graphs of specklegram: a novel approach

Sankararaman¹

2022

Phys. Scr.

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The advancement in thin-film technology necessitated the development of more reliable, sensitive, and non-destructive methods for the quality analysis of thin films. Graph theory, the mathematical and analytical tool, has gained significant importance in analysing complex signals and images. The paper introduces a novel surrogate method based on graph theory to analyse the specklegrams of thin films for quality analysis. The method is deciphered through the complex network analysis of the electronic specklegrams of the molybdenum oxide thin films sputtered at different Argon pressures. For this, graph features are determined from the graphs constructed using the seven equally spaced columns of the specklegram data of a film. The heat map of the specklegram displays the morphological modifications in the film surface. The study reveals a decrease in the centrality measures and multifractal dimension for the film samples. The decrease of root mean square surface roughness of the films calculated from the atomic force microscopic images suggests its relation with centrality measures indicating the potential of centrality measures of the specklegrams as a surrogate method for thin-film quality analysis.

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Speckle Interferometric Investigation of Argon Pressure-Induced Surface Roughness Modifications in RF-Sputtered MoO3 Film

Cited by 4 publications

References 25 publications

Divulging the Potential of Sodium Carbide Thin Film for Semiconductor Applications

Divulging the Potential of Sodium Carbide Thin Film for Semiconductor Applications

How the Complex Network of Specklegram Deciphers Intra‐Film Thermal Induced Dynamics?

Reflections of thin film surface roughness on graphs of specklegram: a novel approach

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