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Growth window and metal-insulator transition behavior of VO2 thin films deposited by pulsed laser deposition for thermal switch applications
(2026-05-01)
Jessadaluk, Sukittaya
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Rahong, Sakon
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Kayunkid, Navaphun
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Khemasiri, Narathon
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Rangkasikorn, Adirek
Vanadium dioxide (VO<inf>2</inf>) is a strongly correlated transition metal oxide that exhibits a sharp and reversible metal-insulator transition (MIT) near room temperature, making it a promising material for thermal switching and adaptive electronic applications. In this study, VO<inf>2</inf> thin films were deposited on single-crystalline Si, thermally grown SiO<inf>2</inf>, and fused quartz substrates by pulsed laser deposition, and the influence of substrate temperature and oxygen partial pressure on phase formation, structural properties, and MIT behavior was systematically investigated. By optimizing deposition conditions within a narrow oxygen pressure window, phase-pure monoclinic VO<inf>2</inf>(M) thin films with high crystalline quality were achieved while suppressing the formation of over-oxidized vanadium oxide phases. Structural and chemical analyses using X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the stabilization of the V4+ oxidation state and uniform film stoichiometry. Temperature-dependent electrical measurements revealed a pronounced and reproducible MIT characterized by an abrupt change in resistance and a clear thermal hysteresis. In-situ temperature-dependent X-ray diffraction further demonstrated a direct correlation between the monoclinic-rutile structural transformation and the electronic transition. Importantly, the MIT behavior was consistently observed across all investigated substrates, indicating robust film growth and substrate tolerance. These results provide insight into the structure-property relationships governing VO<inf>2</inf> thin films and highlight their potential for integration into thermal switch and thermally adaptive device architectures.
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Sputter-deposited AlN coatings for enhanced tarnish resistance and mechanical durability of silver jewelry
(2026-04-01)
Sudsawad, Kanyarat
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Somjaijaroen, Natthawirot
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Somdock, Nuttakrit
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Sakdanuphab, Rachsak
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Sakulkalavek, Aparporn
Silver jewelry is prone to surface tarnishing caused by sulfur-containing species in ambient environments. In this study, a transparent aluminum nitride–based thin film was deposited by magnetron sputtering and evaluated as a protective barrier against silver tarnishing. Sheets of 99.9% pure silver were coated under various nitrogen flow conditions to optimize film composition and performance. An appropriate nitrogen flow rate of 25 standard cubic centimeters per minute (sccm), corresponding to an N₂/Ar gas ratio of approximately 1:1, was identified for forming AlN-rich films, while an AlN-based film thickness in the range of 80–110 nm was found to be suitable for jewelry protection. X-ray photoelectron spectroscopy analysis showed that insufficient nitrogen availability suppresses complete nitridation, resulting in residual metallic aluminum, which readily reacts with residual oxygen and moisture, increasing the oxygen content in the films. At an N₂ flow rate of 25 sccm, metallic aluminum was suppressed and the films were dominated by Al–N bonding with minor oxygen incorporation, accompanied by the development of a polycrystalline structure. Nanoindentation measurements performed on the 110 nm-thick film yielded a peak hardness of approximately 3.6 GPa, indicating enhanced mechanical durability compared with uncoated silver. Comparative evaluation of color difference, mechanical hardness, tarnish resistance, and environmental durability demonstrated improved performance of the AlN-coated silver. Finally, the practical applicability of the coating was demonstrated by depositing AlN-based films onto large and intricately designed silver jewelry items, indicating compatibility with industrial-scale processing.
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Preparation of CdSe thin films: annealing effects on structure and optical properties
(2025-01-01)
Hankoy, Montree
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Kitiwan, Mettaya
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Tunthawiroon, Phacharaphon
In this work, we prepared well−crystallized CdSe thin films onto glass substrates using vacuum thermal evaporation method (VTE). The CdSe thin film was deposited on the substrate for 10 min in a vacuum chamber where the pressure was maintained at 5⋅10-5 Torr. To further increase the crystallinity, the as-deposited CdSe films were next thermally annealed in the air at annealing temperatures between 200 and 400 °C. The CdSe films were then investigated for phase composition, morphology, and optical properties. X-ray diffraction (XRD) examinations demonstrated a hexagonal phase of CdSe with preferential orientation along the (002) direction. The morphology analysis showed a homogeneous morphology with an average grain of approximately 65.55–90.25 nm in size. Chemical analysis confirmed the stoichiometric presence of Cd and Se. In addition, the optical band gap, determined from Tauc’s plot, using UV-Vis spectroscopic data, was found to be in the range of 1.66–1.69 eV. An annealing temperature of 300 °C resulted in the most favorable condition with the lowest optical band gap value of 1.66 eV, indicating a narrower band gap in the annealed CdSe thin film. The high deposition rate of VTE presents a significant advantage for this technique, potentially facilitating its use in creating optoelectronics and solar cells that are highly efficient and cost-effective.
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Spin Seebeck effect and large spin conversion in amorphous Fe2TiSb/polycrystalline Y3Fe5O12 thin films
(2024-05-30)
Wongjom, Poramed
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Wongjom, Chalothon
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Pongophas, Ekkarat
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Infahsaeng, Yingyot
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Maiaugree, Wasan
This study investigates spin current generation in a Fe<inf>2</inf>TiSb/Y<inf>3</inf>Fe<inf>5</inf>O<inf>12</inf> multi-layer thin film as prepared via the magnetron sputtering method. Comprehensive characterization techniques are employed to assess film properties, including X-ray diffraction, energy-dispersive X-ray spectroscopy, Scanning electron microscopy, and Vibrating sample magnetometer. The Y<inf>3</inf>Fe<inf>5</inf>O<inf>12</inf> material exhibits a polycrystalline ferromagnetic insulator behavior, while the 20 nm-thick Fe<inf>2</inf>TiSb film displays small ferromagnetic metal properties with an amorphous structure. Spin current analysis utilizes the longitudinal spin Seebeck effect configuration, considering magnetic field and temperature dependencies and the results show that spin conversion within the Fe<inf>2</inf>TiSb/Y<inf>3</inf>Fe<inf>5</inf>O<inf>12</inf> structure is influenced by both the spin Seebeck effect and the anomalous Nernst effect, resulting in an overall spin signal enhancement. The spin Seebeck coefficient of Fe<inf>2</inf>TiSb/Y<inf>3</inf>Fe<inf>5</inf>O<inf>12</inf> was approximately 0.103 μV/K within a magnetic field of 300 mT.
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Improvement structure and electrical properties of ITO thin films by annealing treatment
(2024-01-01)
Srithanachai, I.
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Sangwaranatee, N.
In this paper present, the improvement of ITO thin films properties by thermal annealing treatment by various temperature. The process for this investigation various temperature 100-500 ◦C under nitrogen environment, control time for 23 mins. The films crystallization improves after annealing process by XRD results show strong peak after post-annealing and resistivity of thin films shows significant reduced from 1996 to 706 O-cm. The films crystallization shows small peak after thin film growth, however treatment process induced strong peak (222) and (441). The optimization point of treatment process can improve thin films properties that can apply thin films for low energy photodiode.
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Optimization of electrical and optical properties of ITO thin films by annealing in air and nitrogen
(2022-01-01)
Torasa, Chonmapat
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Srithanachai, Itsara
This paper will investigation the optimization of ITO thin films by various thin films deposited time with annealing under air and nitrogen environment. ITO will use for transparent electrode of photodetector that require high transparent and low resistivity. Thin films prepare by using RF sputtering technique by various sputter times 5, 15, 30 and 60 mins then annealing under air and nitrogen for 10 mins, 300 °C. Transparent of thin films after prepared at thickness around 1,166 µm and annealing under nitrogen environment show high transparent 89.8% at wavelength 1,170 nm and low resistivity 2.1 × 10−5 ohm-cm. From the results of transparent and resistivity will get optimize thickness of thin films that use for transparent electrode of photodetector. By optimize thickness of ITO thin films is 413 nm with 87.6% transparent and 0.8 × 10−3 ohm-cm resistivity.
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Novel preparation and characterization of fe2 o3 /cnt thin films for flammable gas sensors
(2019-01-01)
Chaitongrat, Buaworn
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Chaisitsak, Sutichai
In this work, novel preparation for Fe<inf>2</inf> O<inf>3</inf> /CNT thin films was investigated. The Fe/CNT thin films were synthesized through vertical floating-catalyst chemical vapor deposition technique (FC-CVD) and subsequently annealed in air. The various annealing temperature to create Fe<inf>2</inf> O<inf>3</inf> was examined and characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and Raman spectroscopy. In addition, effect of wet/dry process on gas sensing of Fe<inf>2</inf> O<inf>3</inf> /CNTs was also investigated. The results suggest that the interfacial oxide layer helps to significantly improve LPG sensing performance with rapid response and recovery times. The proposed method can be considered as a promising approach for producing ultra-Fe<inf>2</inf> O<inf>3</inf> /CNT thin films that are appropriate for sensing application.
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Properties of manganese oxide films prepared by electrostatic deposition technique
(2018-01-01)
Songkeaw, Potiyan
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Onlaor, Korakot
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Thiwawong, Thutiyaporn
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Tunhoo, Benchapol
In this work, the electrostatic spray deposition technique was applied to prepare manganese oxide tin films. The effects of post annealing at various temperatures on the properties of manganese oxide film were studied. The properties of the films were assessed by X-ray photoelectron spectroscopy and field-emission scanning electron microscope. In addition, the electrochemical properties of the manganese oxide films were investigated. It was found that the prepared films could be used for supercapacitive, energy storage devices.
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Supercapacitive properties of cobalt oxide thin films prepared by electrostatic spray deposition technique at different substrate temperature
(2016-01-01)
Chansaengsri, Kasidid
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Onlaor, Korakot
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Thiwawong, Thutiyaporn
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Tunhoo, Benchapol
In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique. The influence of the substrate temperatures on properties of film was investigated. Phase transformation of cobalt oxide thin films due to the effect of different substrate temperature was also observed. Cyclic voltammetry was used to measure the performance of cobalt oxide supercapacitor. At higher substrate temperature, the cobalt oxide thin films exhibit the high specific capacitance due to the effect of phase transformation in cobalt oxide films.
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Effect of annealing temperature on structural and optical properties of cobalt oxide thin films prepared by electrostatic spray deposition technique
(2016-01-01)
Chansaengsri, Kasidid
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Onlaor, Korakot
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Thiwawong, Thutiyaporn
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Tunhoo, Benchapol
In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique on glass substrate. The influence of the annealing temperature on properties of cobalt oxide film was investigated. The structural, optical and morphology of cobalt oxide thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy, UV-Visible spectrophotometer, scanning electron microscope, respectively. The crystalline parameters such as crystalline size of films can be obtained from XRD spectra. Phase transformation due to the different annealing temperature in cobalt oxide film has been observed. Moreover, at the higher annealing temperature, the optical band gap in cobalt oxide films were shifted to lower value due to the change in crystalline size and the defect sites in films.

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