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Access type: UnknownAuthor: search.filters.author.Tipawan Khlayboonme, S.

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    Reversible thermally stimulated phase transition in amorphous–nanocrystalline β-V2O5 thin films for temperature-sensitive electronics
    (2026-01-01)
    Tipawan Khlayboonme, S.
    ;
    Fungfuang, Natasia
    ;
    Kitiwan, Mettaya
    V<inf>2</inf>O<inf>5</inf> thin films are significant for next-generation temperature-sensitive electronic devices owing to notable phase stability and reversibility. Optimizing phase characteristics toward reversible low-temperature transitions enhances device performance. In this study, thin films of amorphous–nanocrystalline β-V<inf>2</inf>O<inf>5</inf> were deposited on glass substrates using the inclined magnetron head in radio-frequency magnetron sputtering under an O<inf>2</inf> reactive gas. The effects of thermal stimulation (heating to 400 °C, followed by cooling) were investigated for an as-deposited film prepared at 7.5 % O<inf>2</inf> and for two annealed films deposited at 7.5 % and 10 % O<inf>2.</inf> The annealed films were annealed at 300 °C before thermal stimulation. The films were characterized by X-ray diffractometry (XRD), Auger-electron spectroscopy, field-emission electron microscopy, Van der Pauw and Hall effect measurements, and ultraviolet–visible spectroscopy. The as-deposited film exhibited insulating behavior, whereas the annealed films at 7.5 % and 10 % O<inf>2</inf> demonstrated n-type and p-type conductivities, respectively, accompanied by decreased intensity of the V LMM Auger peak. Before thermal stimulation, the as-deposited film was highly amorphous, whereas the annealed films comprised the β-monoclinic phase. Thermal stimulation caused mixed β-monoclinic and β-tetragonal symmetries for all films and induced significant changes in surface morphology, except for the annealed film at 7.5 % O<inf>2</inf>. Variations in carrier density and bandgap energy indicated that thermal energy promoted oxygen vacancies but reduced vanadium vacancies in the film structure. In situ XRD analysis demonstrated the phase stability and reversible formation of the nanocrystalline β-monoclinic phase, revealing potential for thermally responsive applications requiring repeatable phase behavior.
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    Dry film Holographic grating based on computer-generated mask Lithography
    (2022-01-01)
    Inneam, Chanikan
    ;
    Tipawan Khlayboonme, S.
    ;
    Kitiwan, Mettaya
    ;
    Yindeesuk, Witoon
    ;
    Srinuanjan, Keerayoot
    This paper presented an alternative technique for fabricating the dry film holographic grating based on a mask generated by computer simulation and experimental results. The mask was generated by a fringe pattern which is created by the mathematical model of two beams interference with various angles. Computer simulation of the fringe pattern was printed on film, i.e., the holographic grating mask. The mask was attached on dry film and then illuminated by UV light, where the lithography technique was applied. According to the lithography technique, the computer-generated holographic grating mask was transferred to dry film. After fabrication, fringe patterns obtained from the grating were observed. Then, the grating period was analyzed and confirmed by Scanning Electron Microscope (SEM). Experimental results show that the method could apply to fabricate the dry film holographic grating.
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    Effect of two-step deposition process on morphology and optical properties of nanostructured diamond films
    (2013-02-19)
    Tipawan Khlayboonme, S.
    ;
    Techitdheera, W.
    ;
    Thowladda, Warawoot
    The morphology and optical properties of nanostructured diamond films affected by the two-step deposition process with changing CH4 concentration were investigated. The CH4 concentration was 1% for the first step and 2% for the second step. The films were prepared by chemical vapor deposition in a microwave plasma reactor with a CH4/H2 gas mixture. Nanocrystalline columnar-structured diamond film with lowering of sp2-bonded carbon content was achieved by the two-step deposition process. Unlike that of the single-step process with 1%CH4, the two-step process promoted the morphology to more uniform and smoother film. The two-step process increased the higher grain boundary as well as decreased the sp2-bonded carbon content in the film, as compared with the single-step process with 2%CH<inf>4</inf>. © (2013) Trans Tech Publications, Switzerland.
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