Chaisitsak, Sutichai

Preferred name

Alternative Name

Chaisitsak, S.

Main Affiliation

School of Engineering

sutichai.ch@kmitl.ac.th

Now showing 1 - 10 of 18

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Organic vaporensors based on single-walled CNTs
(2006-12-01)
Chaisitsak, Sutichai
;
Chaithongrat, Buaworn
;
Nukeaw, Jiji
;
Tuantranont, Adisorn
An investigation of the influence of organic vapor (ethanol, methanol and acetone) on the characteristics of simple-structure sensors fabricated from single-walled carbon nanotube (SWCNT) thin films is reported. SWCNTs were directly deposited, by using atmospheric pressure CVD using alcohol-ferrocene mist, on the patterned Al electrodes to fabricate a sensor. It was found that the characteristic of SWCNT-based sensors depended on the depositing position in CVD reactor. The sensor response could be optimized by adjusting the depositing position along the inner quartz reactor. The sensor reproducibility could be improved by light soaking after switching to air. © 2006 IEEE.
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F-doped nanocrystalline SnO2 thin films for liquid petroleum gas (LPG) sensors
(2011-10-04)
Chaisitsak, S.
In this paper we reported the improvement sensing performance of nanocrystalline SnO<inf>2</inf> thin film based LPG sensors by doping with fluorine. Un-doped and F-doped tin oxide films were prepared on glass substrates by dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films were nanocrystalline SnO <inf>2</inf>. Gas sensing characteristics (sensor response, response/recovery time and repeatability) of the nanocrystalline SnO<inf>2</inf> sensors based on a planar interdigital structure were investigated at different operating temperatures and different LPG concentrations. The addition of fluorine to SnO<inf>2</inf> was found to be advantageous for efficient detection of LPG gases, e.g. F-doped sensors were more stable at low operating temperature and had higher sensor response and faster response/recovery time, compared to un-doped sensor material. © 2011 IEEE.
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Fast-LPG Sensors at Room Temperature by α -Fe2O3/CNT Nanocomposite Thin Films
(2018-01-01)
Chaitongrat, B.
;
Chaisitsak, S.
We present performance of a room temperature LPG sensor based on α-Fe2O3/CNT (carbon nanotube) nanocomposite films. The nanocomposite film was fabricated via the metallic Fe catalyst particle on CNTs in which both the catalyst particles and the CNT were simultaneously synthesized by chemical vapor deposition (CVD) synthesis and were subsequently annealed in air to create α-Fe2O3. These methods are simple, inexpensive, and suitable for large-scale production. The structure, surface morphologies, and LPG response of nanocomposite films were investigated. Raman spectroscopy and XPS analysis showed the formation of α-Fe2O3 on small CNTs (SWNTs). Morphological analysis using FE-SEM and AFM revealed the formation of the porous surface along with roughness surface. Additionally, the sensing performance of α-Fe2O3/CNTs showed that it could detect LPG concentration at lower value than 25% of LEL with response/recovery time of less than 30 seconds at room temperature. These results suggest that the α-Fe2O3/CNTs films are challenging materials for monitoring LPG operating at room temperature.
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Comparison Between Wet and Dry Transfer FE2O3-CNT Hybrid Thin Films as Room-Temperature Liquefied Petroleum Gas (LPG) Sensors
(2023-12-01)
Chaisitsak, Sutichai
;
Chaitongrat, Buaworn
;
Yahud, Shuhaida
;
Salleh, Ahmad Faizal
FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films are promising candidates for room-temperature gas sensors with high sensitivity, rapid response, and recovery times. In this work, we reported the suitable fabrication strategies of FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films as liquefied petroleum gas (LPG) sensors by comparing the dry (without using aqueous solutions) and wet processes. Fe-CNT hybrid thin films were used as the primary material for synthesizing FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films, which were then annealed in air at 350oC to create α-FE<inf>2</inf>O<inf>3</inf>. Characterizations by X-ray photoelectron spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy (FE-SEM) confirmed the decoration of α-FE<inf>2</inf>O<inf>3</inf> nanoparticles on CNT surfaces. The transfer process had effects on the surface morphology and sensor characteristics. FE-SEM presents that the surface morphology of the wet-transfer FE<inf>2</inf>O<inf>3</inf>-CNT films was web-like structures with a highly porous morphology. Whereas the surface morphology of the dry-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films was a branch-like structure. The I-V relationship of both annealed wet-and dry-films was non-linear indicating the present of n-type α-FE<inf>2</inf>O<inf>3</inf>. Under 5 vol.% of LPG, the wet-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films have higher sensitivity (S = ~ 3% Tresp.= 10 s, trec.= 59s) compared to the dry-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films (S = ~ 1.4%, Tresp.=90s, trec.= incomplete recovery). Moreover, the wet-transferred FE<inf>2</inf>O<inf>3</inf>-CNTs could detect LPG concentration at a lower value than 25% of LEL (Lower Explosive Limit) with rapid response and recovery time of 23 s and 49 s, respectively.
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Fabrication of amorphous silicon nanocones by bias-enhanced microwave plasma CVD
(2007-02-25)
Chaisitsak, Sutichai
We present a simple growth of highly aligned silicon nanocones by using bias-enhanced microwave plasma CVD of gas mixture of hydrogen and methane. SiO<inf>2</inf> and nickel films were used as a silicon precursor and a seeding material for patterning cone structure, respectively. SEM studies showed that the nanocones have nanometer-size tips and sub micrometer-size bases. TEM analysis revealed that the nanocones have amorphous structure with nickel on the tips. The model for formation of silicon nanostructures will also be suggested. © 2006 Elsevier B.V. All rights reserved.
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Spray deposited CuInS2/TiO2 thin film solar cells
(2013-09-02)
Kaliang, J.
;
Chaisitsak, S.
Copper indium sulfide (CIS) solar cells with Ag/CIS/TiO<inf>2</inf>/FTO/ glass structure were fabricated by non-vacuum methods. The nanoporous TiO <inf>2</inf> and nanocrystalline CIS films were prepared by screen-printing and spray pyrolysis techniques, respectively. The obtained films were examined using field-emission scanning electron microscopy and X-ray diffraction. The solar cell properties were characterized under AM 1.5. The porous nature of TiO <inf>2</inf> layer was found to cause the formation of nanocrystalline CIS with a very small grain size within the TiO<inf>2</inf> matrix. The photocurrent could not be observed in any devices without a TiO<inf>2</inf> layer (i.e. CIS/FTO), while it was detected for the devices consisting of TiO<inf>2</inf> layer (i.e. CIS/TiO<inf>2</inf>/FTO). The thickness of TiO<inf>2</inf> layer was optimized for maximum efficiency. The highest efficiency obtained solar cells was 2.3 × 10-5 % (V<inf>oc</inf>: 0.147 V, J<inf>sc</inf>: 6.5×10-7A/cm2, FF: 0.24) with a 3-μm-thick TiO<inf>2</inf>. © 2013 IEEE.
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Parametric study of atmospheric-pressure single-walled carbon nanotubes growth by ferrocene-ethanol mist CVD
(2007-11-01)
Chaisitsak, S.
;
Nukeaw, J.
;
Tuantranont, A.
Uniform web-like films consisting single-walled carbon nanotubes (SWCNTs) were deposited on a silicon substrate using the chemical vapor deposition (CVD) of ferrocene-ethanol mist at atmospheric pressure (∼ 1 atm). The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including deposition position in the reactor, temperature, ferrocene/ethanol ratio, flow rate of carrier gas (argon), and deposition time on the formation of SWCNTs was investigated using high-resolution scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The worm region outside the furnace was found to be a suitable position for the formation of SWCNT films. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotube. The ferrocene concentration in ethanol strongly influenced the amount of impurity particles in the material. Moreover, the intensity of metallic tail in D-band was found to decrease with increasing the flow rate, showing a possibility of the formation of semiconducting SWCNTs. Results of this study can be used to improve understanding of the growth of SWCNTs by floating catalyst CVD of alcohol mist. © 2007 Elsevier B.V. All rights reserved.
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Novel preparation and characterization of fe2 o3 /cnt thin films for flammable gas sensors
(2019-01-01)
Chaitongrat, Buaworn
;
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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Nanocrystalline SnO2: F thin films for liquid petroleum gas sensors
(2011-07-01)
Chaisitsak, Sutichai
This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO<inf>2</inf> films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO<inf>2</inf> with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO<inf>2</inf> was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection. © 2011 by the authors.
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Effects of three parameters on graphene synthesis by chemical vapor deposition
(2013-09-02)
Dathbun, Ajjiporn
;
Chaisitsak, Sutichai
A high quality graphene film on a copper foil was successfully grown by a CVD process using ethanol as a carbon source. The effect of growth temperatures (650-850°C), reaction times (5-50 min) and post-CVD cooling process rates (slow-cooling, fast-cooling and fast-cooling under ethanol exposure) on the formation of graphenes was investigated by Raman spectroscopy and scanning electron microscopy (SEM). The graphene film deposited under the optimal conditions showed features of a high quality such as a high I <inf>2D</inf>/I<inf>G</inf> ratio of ∼8, a low I<inf>D</inf>/I<inf>G</inf> ratio of 0.28 and a narrow full width half maximum (FWHM) of Lorentzian-shaped 2D peak of ∼35 cm-1. It was found that the quality of graphene film could be enhanced by optimizing the growth temperature and time, while the number of graphene layer was less sensitive to the cooling rate. However, the fast cooling process under ethanol exposure was found to be a key process for obtaining graphenes with a large domain size. These findings may help to fabricate high-quality graphenes on a copper foil for electronic applications. © 2013 IEEE.

Chaisitsak, Sutichai

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