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Author: search.filters.author.Buakaew, SeangraweeSubject: search.filters.subject.porous silicon

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    Porous Silicon Formation by Stain Etching on Pyramid Surface in U-Shape MSM Photodetector
    (2024-01-01)
    Muanghlua, Rangson
    ;
    Atiwongsangthong, Narin
    ;
    Vijafun, Jidapa
    ;
    Suttijalern, Kamonwan
    ;
    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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    Porous Silicon Sensing Membrane Electrode on Extended Gate Field Effect Transistor for pH Sensor
    (2023-01-01)
    Atiwongsangthong, Narin
    ;
    Ausama, Atthawit
    ;
    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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    Ambient Gases Sensing by Photoluminescence Properties of Porous Silicon
    (2022-01-01)
    Buakaew, Seangrawee
    ;
    Ausama, Atthawit
    ;
    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.