Phetchakul, Toempong

Preferred name

Alternative Name

Phetchakul, T.

Main Affiliation

School of Engineering

toempong.ph@kmitl.ac.th

Now showing 1 - 10 of 13

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Development of Hetero-Junction Cells with a DLC Film Anti-reflection Layer
(2024-01-01)
Srisantirut, Tanawit
;
Phetchakul, Toempong
Diamond-like carbon (DLC) films were synthesized on glass slides and heterojunction cells by ECR-CVD (Electron-Cyclotron Resonance Plasma-Enhanced Chemical-Vapor Deposition) method using acetylene (C<inf>2</inf>H<inf>2</inf>), nitrogen (N<inf>2</inf>) gases and substate bias at 0,50,100 V. We investigate the effects of varying substrate bias on the characteristics of DLC film and its optical properties. Their characteristics were analyzed using the Raman technique the D and G peaks at approximately 1356 ± 5 cm−1 and 1578 ± 5 cm−1 respectively. The film's surface was examined using AFM imaging. Films with increased substrate biasing tend to exhibit a smoother surface. The film thickness varies depending on substrate biasing and nitrogen doping. The best light transmission was observed in films without substrate biasing. Analysis of the IV characteristics in experimental heterojunction cells revealed that cells with synthesized DLC films showed an efficiency increase from 0.74% to 0.78%. For cells doped with nitrogen, the efficiency rose from 0.74% to 0.79%. The DLC film has hydrogen bonding that can help enhance the efficiency of ITO.
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Magnetic GAA (MAG-GAA) for Vertical and Horizontal Magnetic Field Detection
(2024-01-01)
Swe, Khine Thandar Nyunt
;
Poyai, Amporn
;
Phetchakul, Toempong
The Gate All Around (GAA) is introduced as a magnetic sensor to sense the vertical and horizontal magnetic field applied to the device. Magnetic GAA (MAG-GAA) consisting of one source contact, one gate contact wrapped around the channel, and four drain contacts are created and simulated for the two-dimensional magnetic field detection using Sentaurus. The proposed device structure of MAG-GAA is designed and operated based on the current mode of the Hall effect. The vertical magnetic field is sensed by activating the drain contacts D<inf>1</inf> and D<inf>2</inf>. To detect the horizontal magnetic field, the drain contacts D<inf>3</inf> and D<inf>4</inf> positioned at the top and bottom surfaces of the device are enabled. The differential drain current is obtained as the magnetic response in both detections. MAG-GAA in which the channel length and width are 10 nm and 5 nm respectively is simulated by applying the magnetic field 0.1 T, 0.2 T, 0.3 T, 0.4 T, and 0.5 T in +z, -z, +y, and -y directions. Their respective magnetic responses are illustrated, and the Hall current reaches the highest value at the magnitude of the magnetic field 0.5 T in both cases of magnetic field detection. The sensitivity of MAG-GAA for vertical magnetic field detection is better than its sensitivity for the horizontal magnetic field.
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Magnetic TFET (MAG-TFET)
(2022-01-01)
Boonlua, Thanet
;
Poyai, Amporn
;
Phetchakul, Toempong
This paper presents a new structural magnetic field sensor device. The device structure uses the basic structure of tunneling field effect transistor (TFET). The mechanism uses the current-mode Hall phenomenon with tunneling electron carriers from source to drain. The device structure consists of source, gate and drain with two separate contacts on both sides D1 and D2 to accommodate the amount of current difference (ID) caused by Lorentz's force deflection. The study is carried out by using TCAD simulation. The magnetic field intensity response is linearly dependence. The sensitivity depends on the amount of current and magnetic field intensity. The sensitivity (S) obtained by this device which has width (Fw) 5 nm, length (Lg) 100 nm and height (Fh) 5 nm at biased current of 1000, 100, 10, 1 µA are 0.0133, 0.0263, 0.0812 and 1.22 µA.T-1 respectively. From this experiment, the best relative sensitivity (SR) is 0.000812 T-1 at 100 µA.
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Effect of Substrate Thickness on Horizontal Magnetoresistance
(2020-05-27)
Phetchakul, T.
;
Chemthung, Y.
;
Poyai, A.
This paper presents the effect of substrate thickness on horizontal magnetoresistance that detects the horizontal magnetic field perpendicular to bulk cross section area. The substrate thickness (T) concerns directly to the current density distribution and the effective depth (t) of current path corresponding to cross section area of current. The horizontal magnetoresistance depends on current distribution which concerns with substrate concentration, length, width and thickness of resistor. It changes by the effective depth of current path change by the unbalance between Lorentz's force and Hall electrical force in vertical direction. From this study, the sensitivity of device increases with the thickness of substrate up to critical substrate thickness and still constant for thickness greater than this critical value. The current distribution is limited when substrate thickness less than a critical value and fully distributes when the thickness is greater than this value. At the same constant current, the longer length of resistor shows the lower current density which needs the longer effective depth of current which causes the critical substrate thickness to be increased accordingly.
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Optical Absorption and Bandgap Modulation in Diamond-Like Carbon Films for Anti-Reflection
(2026-01-01)
Srisantirut, Tanawit
;
Pengchan, Weera
;
Phetchakul, Toempong
Diamond-like carbon (DLC) films were deposited onto glass and silicon substrates utilizing Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) with an Argon/Acetylene gas mixture. Substrate biases were varied (0V,-55V,-100V) for both nitrogen-doped and undoped films. Optical band gap (Eg) decreased with increasing negative substrate bias specifically from 2.6 eV to 2.2 eV for nitrogen-doped DLC and from 1.6 eV to 1.3 eV for undoped DLC. Nitrogen doping generally results in films with wider band gaps compared to undoped films at equivalent biases to sp hybrid bond formation increasing bias reduces the band gap within each film type. I-V measurements revealed an increase in open-circuit voltage from approximately 0.648 V to a range of 0.678–0.698 V for cells incorporating nitrogen-doped DLC. This improvement is attributed to enhanced corrosion resistance and electrical conductivity suggesting the suitability of nitrogen-doped DLC for photovoltaic applications.
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Study of Sensitivity and Noise on Magnetic FinFET (MAG-FinFET)
(2023-01-01)
Swe, Khine Thandar Nyunt
;
Poyai, Amporn
;
Phetchakul, Toempong
Three dimensional FinFET device structure is proposed as magnetic device to detect the vertical magnetic field. The region of drain contact is split into two drain contacts and the MAG-FinFET has source contact, gate contact and two drain contacts. Lorentz's force appears as Hall effect when the magnetic field is exposed to the device perpendicularly. The imbalanced drain currents at the drain contact D1 and D2 caused by the expose of magnetic field are measured, and the Hall current is obtained as the output of MAG-FinFET. The relative sensitivities of MAG-FinFET with three channel lengths are calculated. Mixed mode AC analysis simulations are done by using Sentaurus TCAD to study the impact of noise on MAG-FinFET. The fluctuations at the output nodes of Mag-FinFET can be seen as noise voltage spectral density and noise current spectral density. The short channel length of 10 nm MAG-FinFET gives the highest differential drain current and shows the best sensitivity. The limitation of minimum magnetic field is determined from the noise current spectral density obtained at bandwidth 1 Hz to 1 kHz. For channel length 10 nm MAG-FinFET, the minimum magnetic field Bmin 76mTHz is obtained for narrow bandwidth at frequency 1 kHz. The equivalnet magnetic field Beq obtained for large frequency range is 1.28THz.
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MAGFinFET: The channel length effect
(2020-07-01)
Phetchakul, Toempong
;
Pamonchom, Chanvit
;
Poyai, Amporn
This paper studies the channel length effect on MAGFinFET. It is a new magnetic device which its structure is FinFET in nanometer scale. It detects vertical magnetic field like as MAGFET. The parameter is channel length of n channel FinFET which is varied at 10, 20, 30, 40 and 50 nm. The sensitivities at biased current 100 μA of varied channel length are 182.49, 186.41, 190.65, 197.22 and 201.00 nA/T, respectively. It depends linearly on the length of MAGFinFET like as MAGFET in micrometer scale. By comparing with bulk fin channel with the concentration 1015 cm-3, the sensitivity of MAGFinFET and fin resistor at biased current 100 μA are 190.65 and 153.50 nA/T, respectively. The current deflection of induced channel of FinFET is more sensitive than bulk resistor channel in same condition. The induced charges can deflect freely pass through depletion layer in thin fin channel by induced magnetic force not less than or better than in bulk resistor channel.
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High sensitivity non-split drain MAGFET for wireless sensor networks
(2020-08-14)
Nakachai, Rattapong
;
Poyai, Amporn
;
Phetchakul, Toempong
The non-split drain MAGFET proposed in this paper is aspossess an ideal, highest sensitivity in the same type of device, current mode for low power, and low voltage that can be embedded within a system for wireless sensor networks application. It is a split-drain MAGFET that is designed to have no gap between drains so that there is no loss from the gap. There are two split contacts in one drain to represent the split drains for current difference that induced from due to magnetic field. The relative sensitivity comparison among all the gaps (3, 2, 1, and 0 µm) with all aspect ratio of width (W)/length (L) (L/W = 1, 0.6, and 0.2) at biased current 0.25 mA shows that the zero gap or the non-split drain MAGFET structure gives the highest sensitivity. The sensitivities of the non-split drain at the aspect ratios L/W = 1, 0.6, and 0.2 in this study are 0.0595, 0.0479, and 0.0231 T−1, respectively. It is proved that the gap is not necessary for the MAGFET. It is a new, smart way to design the MAGFET for the highest sensitivity and gap lossless for modern sensor applications.
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Diamond-like Carbon Thin Film Coating for Application on Heterojunction Solar Cells by ECR-CVD System
(2020-05-27)
Srisantirut, Tanawit
;
Pengchan, Weera
;
Phetchakul, Toempong
Diamond-like Carbon (DLC) film has the ability to change the refractive index value achieved high transmittance for potential applications of antireflection coating. DLC films were deposited on heterojunction solar cells by the ECR-CVD (Electron Cyclotron Resonance Chemical Vapor Deposition) method using Acetylene (C<inf>2</inf>H<inf>2</inf>) and Argon (Ar) gases. DLC coating affects ITO (Indium tin oxide), causing the electrical and resistivity of heterojunction solar cell vary according to the coating time. The surface and thickness of the DLC films was measured with an atomic force microscope. Illuminated I-V characteristic was investigated by photo-I-V measurements. The suitable acetylene anti-reflection deposition time at 0.40 minutes. Therefore, heterojunction solar cell was fabricated on a substrate using the optimized DLC films as an anti-reflection coating and it obtained an increase efficiency of about 1%.
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A novel dual magnetodiode for wireless sensor networks
(2020-08-14)
Sutthinet, Chalin
;
Poyai, Amporn
;
Phetchakul, Toempong
This paper presents a new magnetodiode, the so-called dual magnetodiode, for wireless sensor application. The device is a current mode which can be integrated with a chip compatible with modern low power, low voltage integrated circuit (IC). The structure and operation are completely different from a conventional magnetodiode. The structure is composed of two p–n junctions in that one region is common and the others are split terminals for output of differential current. The underlying mechanism is carrier deflection by induced force from a magnetic field. The carriers are injected from the common region by forward bias. The defection carriers diffuse, deflect, and recombine along substrate through split terminals according to direction and density of the magnetic field linearly and symmetrically. From the comparison of complementary structure of the split cathode and the split anode structure of L<inf>D</inf> = 50 µm, the bias current 1 mA and magnetic field 0.5 T, the relative sensitivities (S<inf>R</inf>) are 11.01 and 11.19 T−1, respectively. This device is a simple p–n junction structure which is compatible with all micro/nanotechnology.

Phetchakul, Toempong

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