Khlayboonme, S.Tipawan

Preferred name

Alternative Name

Khlayboonme, S. Tipawan

Khlayboonme, S. T.

Main Affiliation

School of Science

s.tipawan.kh@kmitl.ac.th

Now showing 1 - 9 of 9

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Influence of reactive oxygen gas on sputtered-vanadium oxide films under post-annealing in vacuum
(2021-01-01)
Khlayboonme, S. Tipawan
;
Thowladda, Warawoot
Vanadium oxide thin films were deposited on glass substrates by O2 reactive-RF magnetron sputtering from a vanadium (V) target without substrate-heating. The percentages of O2 gas were 10%, 7.5%, 6.0%, 5.0% and 2.5%. The total gas flow rate (O2/Ar) was kept at 25 sccm. As-deposited films were experienced post-annealing process at different temperatures and times. The crystallinity and chemical bonding states of films were examined by X-ray diffraction and Raman spectroscopy. The condition in annealing to active crystallinity depended on an earlier composition of the films. As O2-gas percentages were 10% and 7.5%, after annealing, the as-deposited VxOy films were transformed into crystalline V2O5 films. With decreasing in O2 percentage to 5.0% and 2.5%, the films were transformed into V2O3 and VO films, respectively. The films deposited with 6.0% O2 were crystallized to VO2 with phase B after annealing with 500 °C 15 h. By applying a longer time to 30 h at the high temperature 500 °C in annealing, VO2 films revealed only phase M formation.
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Phase-shifting interferometry for surface roughness measurement on glass substrates
(2014-01-01)
Suriyasirikun, S.
;
Khlayboonme, S. T.
;
Thowladda, W.
Phase-shifting interferometry based on Michelson interferometer is purposed to measure surface roughness of glass slides which are widely used as substrates for thin-film coating processes. For the interferometry system, an optical flat with a flatness of λ/20 is used as a reference mirror. The high accuracy of the phase-shifting is achieved by a piezoelectric-driven linear translation stage of the reference mirror. The reference-phase difference between the twointerfering beams is shifted by every π/2 in phase-shifting. Five frames of interferograms under various phase differences of 0, π/2, π, 3π/2 and 2p are recorded by a CCD camera. Each image pixel of these frames is interpreted to access interference intensity information by five-step phaseshifting algorithm for phase calculation, which in turn relates to surface height. The purpose-built interferometry is tested by the surfaces of two optical flats with flatness of λ/10 and λ/4, which are used as the test surfaces. Our measured flatness results are consistent with those of the commercial optical profilometer. The usefulness of the purpose-built interferometry is demonstrated on two types of the glass slides. Aluminum thin films are also deposited on these glass slides by the RF magnetron sputtering method to enhance reflectivity of the glass slide surfaces. The surface profiles and flatness parameters of these glass slides have been reported. © (2014) Trans Tech Publications, Switzerland.
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Effects of air exposure time and annealing temperature on superhydrophobic surface of titanium dioxide films
(2017-01-01)
Khlayboonme, S. Tipawan
;
Thowladda, Warawoot
TiO<inf>2</inf> thin films coated on glass substrates for self-cleaning applications were prepared by sol-gel dip-coating technique. The influence of annealing temperature and air exposure time on wettability was investigated by a water contact-angle measurement. Thermal annealing at temperatures of 100, 200 and 300 °C in air were conducted to the films. Surface morphology of the films was observed by FE-SEM. Elemental distribution and optical properties were examined by EDX mapping and UV-Vis transmission spectroscopy, respectively. Atomic bonding was confirmed by FTIR. The contact angle reached a maximum when the films were annealed at 200 °C. The contact angles of the as-synthesized films were 61.4±2.7°. During storage in air for 20 days, the contact angles increased to 143.1±2.1°. The films were further reannealed at 100 °C for 20 min, the contact angles were enhanced to 153.1±1.3°. The association of contact angle among the surface morphology, elemental distribution and atomic bonding of the films will be discussed.
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Phase transformation of nanocrystalline diamond films: Effect of methane concentration
(2020-01-01)
Khlayboonme, S. Tipawan
;
Thowladda, Warawoot
Ultra-nanocrystalline diamond films were prepared by a microwave plasma-enhanced chemical vapor deposition reactor using CH4/H2 gas mixture with a power as low as 650 W. The effects of CH4 concentration on nanostructure of the films and gas-phase species in plasma were investigated. The CH4 concentrations of 1.5%, 3.0%, 3.5%, and 4.0% were used and balanced with H2 to a total flow rate of 200 sccm. Morphology and composition of the films were characterized by SEM, Raman spectroscopy and Auger spectroscopy. The gas-phase species and electron density in the plasma were explored by optical emission spectroscopy and plasma-impedance measurement. The increasing CH4 concentration from 1.5% to 4.0% increased C2Hx species and decreased electron density. Phase of the film transform from nano-into ultranano-diamond phase but the growth rate revealingly decreased from 300 to 210 nm/h. Raman spectra indicate the higher CH4 concentration promted phase of the film transiton from NCD to UNCD. While Auger spectra revealed that UNCD film deposited with 4.0%CH4 was composed of 90.52% diamond phase but only 9.48% of graphite phase. The relation between phase transformation of the films and growth mechnism controlled by gas-phase species in the plasma will be dissused.
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RF-sputtered V2O5 thin films on two different glass substrates
(2021-01-01)
Khlayboonme, S. Tipawan
;
Thowladda, Warawoot
Thin V<inf>2</inf>O<inf>5</inf> films were deposited on two different commercial soda-lime glass substrates (A and B) by O<inf>2</inf> reactive radio frequency magnetron sputtering using a vanadium target. The influences of the surface energy and roughness of the substrates on the structure and atomic bonding of the films were examined. The film on substrate A was polycrystalline, with eight crystal orientations, whereas the film on substrate B yielded an intense (001) diffraction peak of α-V<inf>2</inf>O<inf>5</inf> and a weak (200) peak of β-V<inf>2</inf>O<inf>5</inf>, indicating preferred orientation along these planes. Structural analyses indicated that substrate B with lower surface energy and higher roughness enhanced the formation of a layered a-V<inf>2</inf>O<inf>5</inf> structure.
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Comparative study of non-annealing and annealing on properties of ITO deposited by RF magnetron sputtering
(2015-01-01)
Khlayboonme, S. Tipawan
;
Warawoot, Thowladda
A comparison of the properties for two ITO thin films was performed. The two films were as follows - as-deposited and annealed ITO films. The influence of annealing on the structural, morphological, electrical, and optical properties was studied. The post-annealing treatment was done at a temperature of 400 for 1 h in air. The ITO thin films were deposited onto glass substrates by RF magnetron sputtering of a ceramic In<inf>2</inf>O<inf>3</inf>: SnO<inf>2</inf> target in pure argon atmosphere at a low base pressure of <10-6 mbar and a RF power of 50 W. The films were characterized by XRD, FTIR, contact angle measurements, FE-SEM combined with EDX, Halleffect measurements and UV-Vis transmission spectroscopy. The ITO films showed a crystalline structure with a predominant orientation (400) and its intensity was increased after the film was annealed. The structure of the annealed film became reformed in more perfect columnar structure. The annealed film showed a decrease in contact angle and increase in FTIR spectra intensity. The annealing induced more tin incorporated into the film from 0.51 to 2.62 at%. The resistivity decreased from 2.7×10-3 to 1.1×10-3 Ω cm with increasing mobility from 7.5 to 27.5 cm2 V-1 s-1 but decreasing carrier concentration from 3.0×1020 to 2.0 × 1020 cm-3. The optical band gap increased from 3.43 to 3.50 eV. All films showed highly transparency (×85%) in the visible light region. Compared with the non-annealed ITO film, the air-annealed ITO film revealed the better properties except for carrier concentration.
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Nanocrystalline diamond films deposited by two-step approach from CH4/H2 microwave plasma: The influence of reactor pressure
(2013-08-30)
Khlayboonme, S. T.
;
Thowladda, W.
The morphology, growth rate and atomic-bonding structure of nanocrystalline diamond films deposited on Si substrates were investigated under various pressures of the reactor. The films were deposited by CH<inf>4</inf>/H<inf>2</inf> microwave plasma with two-step deposition and H<inf>2</inf>-plasma cleaning processes. The pressures of 1, 2, 5, 9, and 25 kPa were used for deposition. In situ gas-phase species, including electron density, were monitored by an optical spectrometer and impedance analyzer. The films were characterized by SEM, Raman microscope, and white light reflectrometer. When the pressure increased, the surface smoothness and diamond grain size increased, amorphous carbon content decreased, and the intensity ratio of CH/H<inf>β</inf> for the growth step increased. The growth rate was in proportional to the ratio of CH/H<inf>β</inf> for the nucleation step but in inverse proportion to the electron density. The growth rates decreased from 370 nm/h for 1 kPa to 320 nm/h for 2 kPa. After that, the growth rate rapidly increased to 460 nm/h for 9 kPa, but it gradually decreased to 450 nm/h for 25 kPa. The film refractive indices were 2.16 for 5 kPa, 2.21 for 9 kPa, and 2.38 for 25 kPa. The films grown under 1 and 2 kPa showed highly light absorption. © (2013) Trans Tech Publications, Switzerland.
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Plasma impedance tuning effect on nanostructure of diamond films
(2013-10-25)
Thowladda, Warawoot
;
Khlayboonme, S. T.
The morphology and structure of nanocrystalline diamond films as well as the plasma chemistry were studied by altering the plasma impedance. These impedances related to electron density were altered via the matching system. Two films were grown by the microwave plasma under different values of the plasma impedance, resulting in low and high electron densities in the plasma. By the use of measurements of plasma impedance and optical emission, the lowering of an inductive component of the impedance, indicating an increasing electron density, encouraged H-radical concentration present in the plasma. As the plasma was changed to the high electron density, Raman spectra of the films showed the sp3 Raman peak shifted from 1325 to 1328.5 cm-1 with narrower broadening. This behavior arose from an increase in grain size, corresponding to images from a field emission scanning electron microscope. Raman spectra of G-peak position and white light reflectometry showed a reduction in sp2 carbon content of the film. The G-peak shifted from 1564 to 1541 cm-1 and refractive index increased from 1.84 to 2.16. The formation of the films related to the concentrations of H and CH3 radicals. The plasma impedance affected the radical concentrations. © (2013) Trans Tech Publications, Switzerland.
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Effect of SnCl4 concentration on transparent and conducting undoped tin oxide thin films
(2016-01-01)
Khlayboonme, S. Tipawan
;
Thanomngam, Pitiporn
;
Thowladda, Warawoot
The purpose-built pyrolysis system based on an ultrasonically generated aerosol has been successfully used for deposition of highly transparent and conductive undoped tin (IV) oxide thin films. The morphological, structural, optical and electrical properties as well as electronic structures of the films for different concentrations of SnCl<inf>4.</inf>5H<inf>2</inf>O used as the starting precursor were investigated. FE-SEM displayed the substrate surfaces were uniformly covered with the film. The film thickness varied with the precursor concentration. XRD patterns showed the deposited films were a tetragonal phase and presented random orientations. The optical transmission spectra of all films revealed highly transmittance in the visible region. Refractive index of the films was between 1.85 and 2.0. XPS spectra for the Sn 3d<inf>5/2</inf> and Sn 3d<inf>3/2</inf> confirmed that the films were composed of SnO and SnO2 phases. The non-stoichiometric composition decreased with increasing concentration of the precursor. The films deposited with 0.30 M showed the highest conductivity and carrier concentration of 17 ω-1cm-1 and 9.5 x 1019 cm-3, respectively. The disagreement of relation between XPS and Hall measurement suggested the higher carrier concentration arose from incorporation of residual chlorine from the solution precursor during deposition into the films. The interstitially incorporated chlorine considerably influenced the electrical properties of the films.

Khlayboonme, S.Tipawan

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