Onlaor, Korakot
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Preferred name
Onlaor, Korakot
Alternative Name
Onlaor, K.
Main Affiliation
Email
korakot.on@kmitl.ac.th
49 results
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Item type:Publication, Preparation of pH Sensor Based on Extended-Gate Field-Effect Transistor with Spinel ZnCo2O4 Thin Films by Electrostatic Spray Deposition(2023-12-01); ; Electrostatic spray deposition was applied to prepare pH sensing with spinel ZnCO<inf>2</inf>O<inf>4</inf> thin films based on the measurement of extended-gate field-effect transistors (EGFET). The influence of annealing temperatures on the characteristics of the prepared films was analyzed. The structural and morphological properties of the annealed ZnCo<inf>2</inf>O<inf>4</inf> films were assessed by x-ray diffraction, x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and contact angle measurement. The effect of the ZnCo<inf>2</inf>O<inf>4</inf> annealing temperature on the characteristics of pH sensing for the prepared ZnCo<inf>2</inf>O<inf>4</inf> films in EGFET measurement were examined with pH buffer solutions in a pH range of 2–12 at room temperature. The sensing films annealed at 550°C demonstrated a high voltage and current sensitivity at 67.6 mV/pH and 1.033 (µA)<sup>½</sup>/pH, with linearity values of 0.9968 and 0.9991, respectively. Moreover, the annealed 550°C ZnCo<inf>2</inf>O<inf>4</inf> film exhibited low hysteresis at 4.99 mV and high retention stability. The results revealed that the pH sensing of the ZnCo<inf>2</inf>O<inf>4</inf> EGFET device showed a super-Nernstian sensitivity, which indicated the influence of the surface properties of the annealed film. Therefore, the ZnCo<inf>2</inf>O<inf>4</inf> film should be considered a potential option for the pH sensing layer in EGFET applications. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Multilevel conductance switching and carrier transport mechanisms of memory devices based on an ITO/PVK:Ag nanoparticles/Al structure(2018-01-25); ; Multilevel conductance switching was achieved using silver nanoparticles (Ag NPs) embedded in poly(9-vinylcarbazole) (PVK) with a structure of ITO/PVK:Ag NPs/Al. The current-voltage (I-V) curves of the memory devices at low reading voltages showed three distinguished states of current. The memory devices exhibited non-volatile rewritable memory characteristics. The carrier transport mechanisms of the devices in each state were analyzed by theoretical models based on the experimental I-V data. In addition, retention time measurements showed clearly three current states with good data retention properties. From the retention times test, the average values of ON/OFF, ON/intermediate (INTERM) and INTERM/OFF current ratios of the memory devices were 1.7 × 10<sup>6</sup>, 3.5 × 10<sup>2</sup> and 5.0 × 10<sup>3</sup>, respectively. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Supercapacitive properties of cobalt oxide thin films prepared by electrostatic spray deposition technique at different substrate temperature(2016-01-01); ; In this work, cobalt oxide thin films were prepared by electrostatic spray deposition (ESD) technique. The influence of the substrate temperatures on properties of film was investigated. Phase transformation of cobalt oxide thin films due to the effect of different substrate temperature was also observed. Cyclic voltammetry was used to measure the performance of cobalt oxide supercapacitor. At higher substrate temperature, the cobalt oxide thin films exhibit the high specific capacitance due to the effect of phase transformation in cobalt oxide films. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A humidity sensor based on iron oxide films prepared by spin coating process(2017-01-01); In present work, iron oxide films were prepared by spin coating technique. The effect of annealing temperature on the properties of films was investigated. The structural and surface morphology properties of films have been performed by X-ray diffraction, Fourier transform infrared spectroscopy, and field-emission scanning electron microscope. To fabricate the humidity sensor device, the iron oxide film was spun on indium tin oxide transparent electrode. The sensor exhibited the humidity response in the range of 23-93% RH. The mechanisms and equivalent circuit models of sensor can be explained by complex impedance measurement. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Preparation of Conductive Screen-Printing Ink for High-Performance Bendable and Wearable ECG Electrodes on Fabric Substrates(2022-12-15); ; Monitoring of vital signs is a necessary tool to diagnose the symptoms of illness. This work developed screen-printing inks for conductive nanomaterials to fabricate electrocardiogram (ECG)-compatible fabric electrodes. The contents of the polymer matrix, calcium carbonate additive filler, and conductive nanomaterials (silver nanoparticles and copper nanowires) on the resistivity of the composite inks were optimized. A facile process of screen printing was applied to fabricate the electrodes on fabric to create an efficient conductor with high stability in conduction. The fabricated electrodes exhibited flexible and bendable behavior over 0.7% bending strain for wearable components. The results showed that the fabricated electrode based on copper nanowires resistivity was 40.01 ± 1.94 k Ω/cm, and the proposed signal-to-noise ratio (SNR) was approximately 27.16 ± 9.37 dB. Therefore, these fabricated electrodes can be applied in wearable vital biosignal detection devices that perform with high sensitivity during movement, thereby providing health monitoring opportunities. Moreover, the fabricated electrodes can be used without excessive pressure or an electrolyte gel layer, thus overcoming the challenges of developing a portable device. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Influence of post-annealing temperature on the morphological, structural and optical properties of spin coated zinc oxide thin films(2017-01-01) - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Preparation of copper doped zinc oxide nanoparticles by precipitation process for humidity sensing device(2018-09-05); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Transparent write-once-read-many-times memory devices based on an ITO/EVA:rGO/ITO structure(2018-10-01); ; Fully transparent electronic devices play an important role in electronic applications. Well-known examples are the wearable devices and transparent displays; their applications are transparent memory devices of interest. The transparent write-once-read-many-times (WORM) memory devices based on synthesized graphene oxide (GO) blended in poly (ethylene-co-vinyl acetate) (EVA) had been fabricated by a thermal roll lamination technique in which the synthesized GO inside the EVA matrix was reduced into reduced graphene oxide (rGO) during the lamination process. The memory devices exhibited an optical transmittance of more than 60% in the visible light region. The conduction mechanisms of the memory devices were identified using theoretical models based on the current–voltage (I–V) curves. The fitted I–V results were described by the conductive filaments in which electrons were transported through the rGO direct contacts. In addition, the maximum ON/OFF current ratio of the transparent WORM memory device was approximately 5 × 10<sup>5</sup>, and the retention time tests showed two current states with good data retention properties under different temperatures. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A humidity sensor based on silver nanoparticles thin film prepared by electrostatic spray deposition process(2013-07-22); ; In this work, thin film of silver nanoparticles for humidity sensor application was deposited by electrostatic spray deposition technique. The influence of the deposition times on properties of films was studied. The crystal structures of sample films, their surface morphology, and optical properties have been investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-VIS spectrophotometer, respectively. The crystalline structure of silver nanoparticles thin film was found in the orientation of (100) and (200) planes of cubic structure at diffraction angles 2θ = 38.2° and 44.3°, respectively. Moreover, the silver nanoparticles thin films humidity sensor was fabricated onto the interdigitated electrodes. The sensor exhibited the humidity adsorption and desorption properties. The sensing mechanisms of the device were also elucidated by complex impedance analysis. © 2013 Thutiyaporn Thiwawong et al. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Selective electrochemical determination based on magnetic molecularly imprinted polymers for albumin detection(2022-06-01); ; Egg allergy is one of the most common allergies in humans. Allergenic egg protein as ovalbumin is the most abundant protein found in egg white. A selective electrode in electrochemical analysis for albumin from egg white was developed based on magnetic molecularly imprinted polymers (albumin-MMIPs) modified on a screen-printed electrode. Surface modification was applied using methyl methacrylate polymer to create surface specificity for albumin protein. The modified surface was characterized by a field-emission scanning electron microscope (FE-SEM). The average pore size was obtained by Brunauer-Emmett-Teller (BET) analysis, and the potentiostat obtained all electrochemical analysis. The albumin-MMIP electrode was selectivity with albumin, comparison with gluten, glycine, casein, and glucose. The modified electrodes present selectivity of 1.13 × 104 μAg-1ml and a limit of detection of 0.18 mg ml-1. The electrode can be applied to albumin protein detection in solution form in food industries.