Thai Microelectronics Center

Chachoengsao, Thailand

Thai Microelectronics Center

Chachoengsao, Thailand
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Tangcharoen T.,King Mongkut's University of Technology Thonburi | Ruangphanit A.,Thai Microelectronics Center | Pecharapa W.,King Mongkut's University of Technology Thonburi
Ceramics International | Year: 2013

In this work, nanocrystalline M-Zn ferrites (M=Ni; Mn; Cu) with compositions of M1-xZnxFe2O4 (x=0.0, 0.2 and 0.4) were synthesized from metal nitrate precursors by rapid the sol-gel combustion method using diethanolamine (DEA) as the fuel. As-synthesized powders were calcined at 1000 °C for 4 h. The crystal structures and morphologies of these compounds were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The chemical interaction of ferrite powders was investigated by Fourier transform infrared spectroscopy (FTIR). The magnetic properties of after-calcined nanoparticles were measured at room temperature using a vibrating sample magnetometer (VSM). The single phase spinel cubic structure formation is confirmed by XRD and FTIR results. Meanwhile FE-SEM micrographs show the appearance of both undoped and Zn-doped ferrite ceramic samples. In addition, the VSM analyses indicate that the Zn content has a significant influence on the magnetic properties such as saturation magnetization (Ms) and coercivity (Hc). © 2012 Elsevier Ltd and Techna Group S.r.l.


Phetchakul T.,King Mongkut's University of Technology Thonburi | Poonsawat S.,King Mongkut's University of Technology Thonburi | Poyai A.,Thai Microelectronics Center
2016 13th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technology, ECTI-CON 2016 | Year: 2016

This paper presents the new model of 5-contacts vertical Hall device. Despite of the induced force from Hall electric field act upon the current along the contacts for induced Hall voltage, there are some deviation currents from the middle contact that contribute the Hall voltage. The deviation current pass through the bulk resistance causes the voltage drop between the voltage contacts. From this study for n-type substrate, the deviation current created voltage about 20-30 percent of the total Hall voltage that mean it is the importance mechanism for vertical Hall device. This study used 3-D simulation by Sentaurus TCAD. © 2016 IEEE.


Pengchan W.,King Mongkut's University of Technology Thonburi | Phetchakul T.,King Mongkut's University of Technology Thonburi | Poyai A.,Thai Microelectronics Center
Advanced Materials Research | Year: 2012

This paper is proposed to extract the local carrier generation lifetime from forward current-voltage (I-V) characteristics of p-n junctions in case of non-uniform defects. The different geometry p-n junctions have been fabricated by a standard CMOS technology. The forward I-V and high frequency capacitance-voltage (C-V) characteristics of p-n junctions have been measured. The recombination current density can be extracted from the area forward current density by subtracting with the area diffusion current density. Form the recombination current density, the local generation and recombination lifetime can be obtained.


Paipitak K.,King Mongkut's University of Technology Thonburi | Paipitak K.,ThEP Center | Kahattha C.,King Mongkut's University of Technology Thonburi | Kahattha C.,ThEP Center | And 4 more authors.
Energy Procedia | Year: 2011

Ti-doped WO3 electrochromic thin films were deposited onto F-doped tin oxide (FTO) substrates using spin coating technique. The as-deposited films prepared with various concentration of titanium were annealed in air at 500°C. The effect of Ti-doping concentration on structural, surface morphology and optical properties of the films were characterized by X-ray diffractometer, scanning electron microscope and UV-VIS spectrophotometer. The results show that the crystalline of WO3 can be identified at 2θ values of 24.14° corresponding to 200 orientation. In addition, It was found that the electrochromic performance of WO3 can be enhanced by small doping concentration of titanium due to structural modification of the films. © 2011 Published by Elsevier Ltd.


Pengchan W.,King Mongkut's University of Technology Thonburi | Phetchakul T.,King Mongkut's University of Technology Thonburi | Poyai A.,Thai Microelectronics Center
Journal of Crystal Growth | Year: 2013

This paper is proposed to extract the local carrier generation and recombination lifetime from forward characteristics of diode. The different geometry p-n junctions have been fabricated by a standard CMOS technology. Among a variety process steps, implantation step may generate defects. Therefore, the local implantation-induced defects have been studied from the defect activation energy, which has been obtained from the ratio of the local carrier generation and recombination lifetime. The forward current-voltage (I-V) and high frequency capacitance-voltage (C-V) characteristics of p-n junctions have been measured in order to obtain the local carrier generation and recombination lifetime. The calculated activation energy from this method gave reasonable values comparing with the ones obtained from the Arrhenius plot of the reverse current. © 2011 Elsevier B.V.


Srithanachai I.,King Mongkut's University of Technology Thonburi | Ueamanapong S.,King Mongkut's University of Technology Thonburi | Poyai A.,Thai Microelectronics Center | Niemcharoen S.,King Mongkut's University of Technology Thonburi | Yupapin P.P.,King Mongkut's University of Technology Thonburi
Optics and Laser Technology | Year: 2012

We present new experimental results for the electrical behaviors of PN junction diodes irradiated by X-rays. The currentvoltage (IV) characteristics of the PN junction diodes were measured at room temperature. The reverse and forward current before and after irradiation can be explained relative to the following parameters: carrier generation lifetime (τg), ideality factor (n), series resistance (Rs), and sheet resistance (ρ). After irradiation at 40 and 55 keV, a small increment in the diode leakage current was seen, while at 70 keV of exposure, the leakage current was slightly decreased. On the other hand, the forward current was dramatically increased by about three orders of magnitude. In addition, the series resistance of the diodes was confirmed to be positively modified by the use of the soft X-ray annealing method. © 2011 Elsevier Ltd. All rights reserved.


Inceesungvorn B.,Chiang Mai University | Teeranunpong T.,Chiang Mai University | Nunkaew J.,Chiang Mai University | Suntalelat S.,Thai Microelectronics Center | Tantraviwat D.,Thai Microelectronics Center
Catalysis Communications | Year: 2014

A novel NiTiO3/Ag3VO4 composite with type-II band alignment was prepared using a modified Pechini/precipitation method. The FESEM image of the NiTiO3/Ag3VO4 heterostructure reveals the dispersion of small NiTiO3 particles on the Ag3VO4 surfaces, indicating the close interfacial connection between NiTiO3 and Ag3VO4. The heterojunction shows remarkably higher photocatalytic activity than pure NiTiO3 and Ag3VO4 due to an increase in light harvesting efficiency and an efficient electron-hole separation being induced by the suitably matching conduction and valence band levels. Based on the VB-XPS and UV-vis DRS results, a possible electron-hole transfer mechanism at the NiTiO3/Ag3VO4 interface is proposed. © 2014 Elsevier B.V.


Wangkawong K.,Chiang Mai University | Tantraviwat D.,Thai Microelectronics Center | Phanichphant S.,Chiang Mai University | Inceesungvorn B.,Chiang Mai University
Applied Surface Science | Year: 2015

The energy band diagram and band offsets of the novel CoTiO3/Ag3VO4 heterojunction photocatalyst are investigated by X-ray photoelectron spectroscopy for the first time. Excluding the strain effect, the valence-band and conduction-band offsets are determined to be 0.2 ± 0.3 eV and -0.6 ± 0.3 eV, respectively. The CoTiO3/Ag3VO4 composite forms a type-II heterojunction, for which the photogenerated charge carriers could be effectively separated. The results suggest that determination of the energy band structure is crucial for understanding the photogenerated charge transfer mechanism at the interfaces, hence the corresponding photocatalytic activity and would also be beneficial to the design of new and efficient heterostructure-based photocatalysts. © 2014 Elsevier B.V. All rights reserved.


Wangkawong K.,Chiang Mai University | Suntalelat S.,Thai Microelectronics Center | Tantraviwat D.,Thai Microelectronics Center | Inceesungvorn B.,Chiang Mai University
Materials Letters | Year: 2014

A novel CoTiO3/Ag3VO4 composite is successfully synthesized by ethylene glycol-mediated route/hydrothermal method. X-ray diffraction study suggests that the composite is formed with high purity. The presence of Ag3VO4 irregular agglomerates and CoTiO3 rods in the composite is evidenced by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. Photocatalytic degradation experiment under visible light irradiation (λ>400 nm) indicates that the activity of Ag3VO4 is significantly enhanced upon coupling with CoTiO3. Based on the obtained results, such enhanced photoactivity is mainly ascribed to the increased visible-light harvesting ability and the efficient separation of electron-hole pairs of the hybrid photocatalyst. © 2014 Elsevier B.V.


Thongkham W.,Chulalongkorn University | Thongkham W.,Research Center in Thin Film Physics | Pankiew A.,Thai Microelectronics Center | Yoodee K.,Chulalongkorn University | And 3 more authors.
Solar Energy | Year: 2013

The fabrication of Cu(In,Ga)Se2 (CIGS) thin film solar cells on flexible stainless steel (SS) foils or Na free substrates needs the impurity blocking barrier to prevent the diffusion of undesired elements from the substrate into the CIGS as well as the addition of alkali doping especially Na in the CIGS absorber layer. The amount Na in terms of the thicknesses of NaF was varied from 30Å to 200Å in order to study its contributions to the efficiency of the CIGS solar cells. The results show that the Na content in the CIGS films has a direct influence to the open-circuit voltage leading to the energy conversion efficiency and affects the distribution of Ga in the CIGS film. The influence of Na was studied and compared, based on the results of the performance of the solar cells, by using the NaF co-evaporation in various steps during the CIGS deposition process. The optimum thickness of NaF is approximately 50Å to achieve the maximum efficiency of 15.8% without antireflection coating. In addition, the quantum efficiency (QE) indicated different absorption in the long wavelength regions depending upon the methods of Na addition. © 2013 Elsevier Ltd.

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