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Interdigitated Extended Gate Field Effect Transistor for pH Sensor Based on Porous Silicon Layer
(2025-01-01)
Atiwongsangthong, Narin
Study introduces a pH sensor utilizing an interdigitated extended gate field-effect transistor (IEGFET) structure, incorporating a porous silicon (PS) layer. The PS layer was created via electrochemical etching on p-Type <100> silicon wafers, apply current density of 10 mA/cm2 in a 48% HF solution for a duration of 10 minutes. Surface characteristics of the resulting PS layer were examined through scanning electron microscopy (SEM). The sensor integrates this PS layer with a standard N-MOSFET, forming the IEGFET configuration. Due to increasing surface area inherent in porous structure, device demonstrated improved pH sensitivity and response linearity. The sensing capability was tested across pH levels 4, 7, and 10. Results revealed a current mode sensitivity of 0.7636 μA2/pH and a linearity of 99.89%. Voltage mode sensitivity of 53.5 mV/pH and a linearity of 99.86%. These findings validate porous silicon as an excellent for efficient and reliable pH sensing.
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Porous Silicon Formation by Stain Etching on Pyramid Surface in U-Shape MSM Photodetector
(2024-01-01)
Muanghlua, Rangson
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Atiwongsangthong, Narin
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Vijafun, Jidapa
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Suttijalern, Kamonwan
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Niemcharoen, Surasak
In this paper, the porous silicon formation on pyramid surface in U-shape MSM photodetector was studied. Stain etching technique was used to prepare porous silicon material. The solution for stain etching contained the mixed solution of hydrofluoric acid (HF), nitric acid (HNO<inf>3</inf>) and deionized water (DI) with ratios 1: 3: 5 and used halogen lamp expouse 30,000 lux between etching for excite porous formation in 2 minutes. Porous silicon was fabricated on pyramid surface in U shape which between metal electrode titanium and aluminum on p-type silicon 20-25 Ω-cm to reduce the reflection of incident light and to increase a photocurrent of MSM photodetector. In the final part of this paper are the comparison physical morhhology and electrical characteristic of porous silicon on pyramid surface in U shape MSM photodetector with pyramid in U-shape MSM photodetector without porous silicon on the surface and planar MSM photodetector. The physical morphology of porous silicon on pyramid surface in U-shape was studied by using scanning electron microscopy (SEM). The electrical characteristic was investigated by using incident light with wave length 635 nm and power 6 mW at bias voltage 10 V. The result of comparison, we found that porous silicon on the surface of pyramid in U-shape MSM photodetector is rougher than pyramid in U-shape MSM photodetector without porous silicon on the surface. The electrical characteristic of porous silicon on pyramid surface in U-shape MSM photodetector respond incident light higher than pyramid in U-shape MSM photodetector without porous silicon on the surface. Therefore the forming porous silicon on the suface of pyramid in U-shape MSM photodetector is appropriate for the fabrication of MSM photodetector with high photocurrent.
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Three-Phase Oscillator with Cascade Ability Using Voltage Current Conveyor
(2024-01-01)
Buakaew, Seangrawee
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Narksarp, Wipavan
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Choeysombat, Kamonthip
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Kanjanawiwin, Juthamas
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Atiwongsangthong, Narin
This paper presents a new circuit configuration employing voltage current conveyors (VCII) in conjunction with a minimal number of passive elements to achieve a voltage mode sinusoidal oscillator with a 3 -phase differential output. The proposed circuit features a straightforward architecture, with all passive elements connected to low-impedance nodes. Consisting solely of identical VCIIs without multiple outputs, the circuit facilitates the cascading of the 3 -phase outputs without requiring supplementary buffering. Simulation results obtained through PSPICE, along with experimental validation using commercial ICs, are provided to substantiate the efficacy of the proposed circuit.
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Porous Silicon Sensing Membrane Electrode on Extended Gate Field Effect Transistor for pH Sensor
(2023-01-01)
Atiwongsangthong, Narin
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Ausama, Atthawit
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Buakaew, Seangrawee
In this paper, we used porous silicon as sensing membrane electrode which were formed by using anodization etching process at room temperature. Porous silicon sensing membrane electrode will be combined working with commercial N-MOSFET which used as the extended gate field effect transistor (PS-EGFET) for pH sensor. P-Type silicon wafer was used as material substrate for prepare porous silicon sensing membrane electrode. Anodization parameters, the current density of 10 mA/cm2, with 48% hydrofluoric acid concentration and etching time of 10 minutes. The pH sensing of porous silicon EGFET were measured in pH value of 4, 7 and 10, respectively. From experiment, the porous silicon EGFET were exhibited high pH sensitivity on current mode in relationship between the drain current with pH value was $0.2929\ \mu\mathrm{A}^{1/2}/\text{pH}$, corresponding to the linearity of 99.72%. And, pH sensitivity on voltage mode in relationship between reference voltage with pH value was 34.8 mV/pH, corresponding to the linearity of 99.78%. The experiment results showed that the porous silicon was suitable sensing membrane material for pH sensor.
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Adjustable Quadrature Shadow Sinusoidal Oscillator
(2022-01-01)
Buakaew, Seangrawee
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Atiwongsangthong, Narin
This article presents a shadow oscillator with quadrature-phase outputs. The proposed circuit employs the voltage differential transconductance amplifier (VDTA) and two grounded passive elements. The frequency of the oscillation, as well as the condition of oscillation, are accomplished through the tunning of the gains of the external amplifiers. Therefore, frequency adjustability can be performed without the effect on the biquad cell which is the main feature of the shadow oscillators. The results from the PSpice simulations employing the CMOS circuit level are included to verify the proposed quadrature shadow oscillator configurations.
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Ambient Gases Sensing by Photoluminescence Properties of Porous Silicon
(2022-01-01)
Buakaew, Seangrawee
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Ausama, Atthawit
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Atiwongsangthong, Narin
Ambient gas sensing was responced by photoluminescence intensity properties of porous silicon. Silicon wafer was used as starting material for porous silicon samples, anodization etching process was used to prepare porous silicon layer on p-type silicon substrate. Anodization parameters, the current etchings used between 10 to 40 mA/cm2, with 48% hydrofluoric acid concentration and etching time of 10 minutes. The porous silicon structure were described by using SEM and the porosity of samples by gravimetric technique. The samples were applied as ambient gas sensing were described by photoluminescence intensity at room temperature. The bad of photoluminescence intensity when porous silicon was stored in oxygen ambient gas and the best of photoluminescence intensity was to vacuum.
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The Study of Porosity and Photoluminescence Properties of Nanoporous Silicon Layer under Anodization Current Density Formation by Double Tank Electrochemical Etching Cell
(2021-04-01)
Atiwongsangthong, Narin
This research presents the effect of the constant current density on nanoporous silicon formation by double tank electrochemical etching cell without coating aluminum on the backside of silicon wafer. In this paper, the constant current density is increased from 10 mA/cm2 to 25 mA/cm2 during the anodization process by using hydrofluoric acid and ethanol at ratio 4:1 and the etching time are 10 minute. Gravimetric and Photoluminescence measurement were performed to investigate the porosity and the uniform distribution of nanoporous silicon layer respectively. The result shows that the porosity of nanoporous silicon layer was increased when the constant current density increased. The range of the porosity 46% to 80% and it is dependent on constant current density. The photoluminescence measurement with irradiate ultraviolet light on the surface of samples it was observed that hight uniformity of photoluminescence intensity. Indicates that the nanoporous silicon surface are more uniform distribution. This research discovers that the constant current density has large effect on the porosity of nanoporous silicon layer. Results show good improvement the nanoporous silicon formation by double tank electrochemical etching cell without coating aluminum on the backside of silicon.
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Water Repellent Modified Polyester Fabric Based Triboelectric Nanogenerator for Harvesting Human Mechanical Energies
(2021-01-01)
Pharino, Utchawadee
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Ausaman, Kanyamon
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Phonimdang, Kunyapak
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Pongampai, Satana
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Vittayakorn, Wanwilai
Wearable triboelectric nanogenerators (TENGs) for converting human mechanical energies into electricity are being investigated widely, because of their potentially diverse applications that come from wearable power supplied to multifunctional self-powered sensing. However, external influences, such as water or high humidity, seriously degrade the electrical output of TENGs. Therefore, a simple method was implemented for fabricating a water repellent fabric-based TENG for harvesting human mechanical energies. Polytetrafluoroethylene (PTFE) or SiO<inf>2</inf> modified by trichloro(octadecyl)silane (OTS) were sprayed onto a polyester (PET) fabric surface to increase hydrophobicity. The PTFE and SiO<inf>2</inf>/OTS coated polyester fabrics exhibited excellent water repellency with a high-water contact angle of ∼144° and ∼153°, respectively. The surface morphology of the coated fabrics showed roughness with a granular structure, which was responsible for air entrapment that prevented water from penetrating the fabric. Furthermore, electrical output of conventional PET fabric-based TENG was found to improve with the deposition of PTFE particles on the fabric surface. By pairing the PTFE coated fabric with aluminum (Al) tape, in order to fabricate TENG, the device generated a maximum voltage of 10.2 V and short-circuit current of 0.20 µA, with a power output of 0.23 (Formula presented.) W/cm<sup>2</sup>, which is 14 times greater than that of SiO<inf>2</inf>/OTS coated fabric-based TENG. The process for achieving water repellent fabric is simple, and the coating materials are available. Thus, a water repellent fabric-based TENG is promising for large-scale production of wearable harvesters from power supplied to multifunctional self-powered sensing.
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Study of Nitride Thickness on Sensitivity IDEs Humidity Sensor Based on Graphene Oxide Sensing
(2020-03-01)
Pongampai, Satana
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Pengpad, Puttapon
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Meananeatra, Rattanawan
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Atiwongsangthong, Narin
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Muanghlua, Rangson
An interdigitaged electrodes (IDEs) humidity sensor was patterned like a combs by lithography process based on silicon bulk substrate with different nitride thickness (50, 100 and 150 nm). This research studied an effect of thick nitride on sensitivity of IDEs humidity sensor based APTES adhesive layer with graphene oxide (GO) sensing material. The IDEs humidity sensor based on GO was comparatively examined all thick nitride conditions. Capacitance value of fresh IDEs humidity sensor shown not significant change all nitride thickness but it affected to sensitivity after GO coating due to high GO densified onto IDEs surface. Scanning Electron Microscope (SEM) was analyzed GO distribution and surface morphology. Raman spectroscopy clearly revealed the GO presence. The sensitivity from 50 to 80 %RH for optimal 100 nm thick nitride shows improvement to 2.78 and 1.27 times or 278.35% and 127.46% based on 50 and 150 nm thick nitride, respectively. Furthermore, the optimal condition of IDEs humidity sensor shows a little response and recovery times (11 and 7 sec), low hysteresis (3.21%), fine repeatability as well as high accuracy on long-term ability test. It clearly demonstrated for high sensitivity of nitride IDEs humidity sensor based on GO sensing film deposition.
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The study of trivalent-dopants effect on electrical properties of the BaZr0.7In0.3O3-δ system
(2019-01-02)
Poolphol, Phieraya
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Muanghlua, Rangson
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Atiwongsangthong, Narin
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Vittayakorn, Wanwilai
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Vittayakorn, Naratip
Perovskite BaZrO<inf>3</inf> and BaZr<inf>0.7</inf>In<inf>0.3</inf>O<inf>3-δ</inf> (BZI) ceramics were prepared via solid-state reaction. The crystal structure, dielectric and electrical properties of these ceramics were analyzed comparatively. Rietveld analysis indicated that BaZrO<inf>3</inf> and BaZr<inf>0.7</inf>In<inf>0.3</inf>O<inf>3-δ</inf> (BZI) have cubic symmetry with the Pm (Formula presented.) m space group. A small amount of In<inf>2</inf>O<inf>3</inf> was observed in the BZI ceramic. The lattice parameter (a) decreased when a small amount of In<sup>3+</sup> was added. The relative permittivity ε<inf>r</inf>(T) and tan δ(T) of BZ and BZI ceramics behaved as plateaus that were independent of frequency and temperature in a temperature range of below 150 ̊C and 50 ̊C, respectively, which ascribed to the intrinsic dielectric properties resulting from electronic and/or ionic polarization. By increasing the temperature further, both ceramics exhibited colossal dielectric constant (CDC) behavior. Conductivity was greater with increasing temperature, which corresponded to Arrhenius behavior. Activation energies were calculated as 0.522 and 0.620 eV for the BZI and BZ system, respectively.

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