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    A planar nanoporous silicon metal-semiconductor-metal visible light photodetector
    (2013-11-01)
    Atiwongsangthong, Narin
    In this work, the nanoporous silicon layer is prepared through the simple electrochemical etching of p-type crystalline silicon wafer in a hydrofluoric acid solution under various anodization conditions such as the resistivity of the silicon wafer, current density, concentration of the hydrofluoric acid solution and anodization time. The gravimetric method and SEM images have been used to characterize the morphological on the various porosity of nanoporous silicon layer. Two square Al Schottky contacts were thermally deposited on the nanoporous silicon layer with the electrode spacing is 500 μm to form a planar nanoporous silicon metal-semiconductor-metal (MSM) visible light photodetector. In experiment, we investigated photoresponse and the response time of a planar nanoporous silicon MSM visible light photodetector which was fabricated on the various porosity of a nanoporous silicon layer. It is found that when devices are fabricated on a higher porosity nanoporous silicon layer, the photoresponse of the device will expand toward the shorter-wavelengths and the bandwidth of the spectrum response will cover visible light. In addition, it is found that the response time of the device decreases. © 2013 American Scientific Publishers All rights reserved.
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    Investigations of nanostructure and photoluminescence properties of nanoporous silicon
    (2013-10-04)
    Atiwongsangthong, Narin
    In this paper, the nanoporous silicon layer was formed by electrochemical etching of silicon wafer in hydrofluoric acid solution. The purpose of this research, the nanoporous silicon layer were investigated the nanostructure and photoluminescence properties. We report the investigation on nanostructure of nanoporous silicon by using SEM, the gravimetric and fourier transform Raman spectroscopy (FT-Raman) technique. It is found that increasing the constant current density between electrochemical etching have effect to increasing porosity of nanoporous silicon. And increasing porosity of nanoporous silicon is effect from decreasing average size of silicon crystallites in nanoporous silicon which can confirm with Raman spectroscopy. The Changes in the photoluminescence intensity of nanoporous silicon samples are studied during nanoporous silicon stored in various ambient gases such as air, nitrogen, oxigen and vacuum. From data of this experiment when nanoporous silicon were stored in ambient air for a long time, the photoluminescence intensity of nanoporous silicon will decrease. In addition, we found strongly decreasing in its photoluminescence intensity when nanoporous silicon were stored in ambient of oxygen which can confirm by using fourier transfrom infrared spectroscopy (FT-IR) technique. © (2013) Trans Tech Publications, Switzerland.
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    Alcohol vapor detection by using nanoporous silicon as based sensor
    (2013-01-01)
    Atiwongsangthong, Narin
    ;
    Niemcharoen, Surasak
    In this paper, we are concerned with fabrication of alcohol vapor sensor based on nanoporous silicon. In order to use nanoporous silicon as alcohol vapor sensor, we made nanoporous silicon onto p-type silicon wafer by electrochemical etching of silicon wafer in hydrofluoric acid solution. The structure of this sensor consists of nanoporous silicon layer and aluminum electrode which is deposited on the top of nanoporous silicon layer by evaporator. In this research, we are concerned the variation of electrical properties of this sensor due to presence of different concentration of alcohol vapor. From the experiment, it is found that this sensor can detect the different concentrations of alcohol vapor in the rang 1000 ppm to 250 ppm.
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    Application of nanoporous silicon for a metal-semiconductor-metal visible light photodetector
    (2011-01-01)
    Atiwongsangthong, Narin
    ;
    Niemcharoen, Surasak
    ;
    Titiroongruang, Wisut
    In this paper we present a study on the application of nanoporous silicon to an optoelectronic device called a nanoporous silicon metal-semiconductor- metal (MSM) visible light photodetector. This device was fabricated on a nanoporous silicon layer which was formed by electrochemical etching of a silicon wafer in a hydrofluoric acid solution under various anodization conditions such as the resistivity of the silicon wafer, current density, concentration of the hydrofluoric acid solution and anodization time. The structure of this device has two square Al/nanoporous silicon Schottkybarrier junctions on the silicon substrate and the electrode spacing is 500 μm. The experiment will study photoresponse and the response time of a nanoporous silicon MSM photodetector which was fabricated on the various porosity of a nanoporous silicon layer. It is found that when devices are fabricated on a higher porosity nanoporous silicon layer, the photoresponse of the device will expand toward the short-wavelength and the bandwidth of the spectrum response will cover visible light. In addition, it is found that the response time of the device decreases. Copyright © 2011 American Scientific Publishers All rights reserved.
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    Nanoporous silicon metal-semiconductor-metal visible light photodetector
    (2010-01-01)
    Atiwongsangthong, Narin
    In this research, we present the study on the application of nanoporous silicon for optoelectronic device which called nanoporous silicon metal-semiconductor-metal (MSM) visible light photodetector in this paper. This device was fabricated on nanoporous silicon layer which was formed by electrochemical etching of silicon wafer in hydrofluoric acid solution under various anodization condition such as the resistivity of silicon wafer, current density, concentration of hydrofluoric acid solution and anodization time. The structure of this device has two square Al/nanoporous silicon Schottky-barrier junctions on the silicon substrate and the electrode spacing is 500 μm. The experiment will study on photoresponse and responsetime of nanoporous silicon MSM photodetector which was fabricated on various porosity of nanoporous silicon layer. It is found that when devices fabricated on higher porosity nanoporous silicon layer, the photoresponse of device will expand toward the short-wavelength and bandwidth of spectum response will cover visible light. In addition, it is found that responsetime of device decreases. ©ICROS.
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    Nanoporous silicon metal-semiconductor-metal photodetector
    (2010-01-01)
    Atiwongsangthong, N.
    ;
    Niemcharoen, S.
    ;
    Titiroongruang, W.
    In this paper we present a study on the application of nanoporous silicon to an optoelectronic device called a nanoporous silicon metal-semiconductor- metal (MSM) visible light photodetector. This device was fabricated on a nanoporous silicon layer which was formed by electrochemical etching of a silicon wafer in a hydrofluoric acid solution under various anodization conditions such as the resistivity of the silicon wafer, current density, concentration of the hydrofluoric acid solution and anodization time. The structure of this device has two square Al/nanoporous silicon Schottky-barrier junctions on the silicon substrate and the electrode spacing is 500 μm. The experiment will study photoresponse and the response time of a nanoporous silicon MSM photodetector which was fabricated on the various porosity of a nanoporous silicon layer. It is found that when devices are fabricated on a higher porosity nanoporous silicon layer, the photoresponse of the device will expand toward the short-wavelength and the bandwidth of the spectrum response will cover visible light. In addition, it is found that the response time of the device in terms of rise time will decrease. © 2010 World Scientific Publishing Company.