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Measurement of UV from a Microplasma by a Microfabricated Amorphous Selenium Detector – January 2013

S Abbaszadeh, KS Karim, V Karanassios-IEEE Transactions on Electron Devices, Vol 60 (2), 2013
We spectrally demonstrate for the first time that an amorphous selenium metal–semiconductor–metal detector can be used for the measurement of ultraviolet photons (200–400 nm) generated from a portable battery-operated microplasma that is used as a light source. An advantage of this low-cost detector is that the device structure allows photons to strike the light-sensitive layer directly rather than through electrodes or blocking layers. Another advantage is that despite operation at high electric fields of up to 43 $hbox{V}/muhbox{m}$, the dark current of the detector at room temperature is 3 $hbox{pA}/hbox{mm}^{2}$. Therefore, detector cooling is not required, and this facilitates portability for measurements on-site (i.e., in the field and away from a laboratory). Spectral response was monitored using a scanning monochromator, and it was compared with that obtained by a portable spectrometer fitted with a linear charge-coupled device detector. To demonstrate detector responsivity, emission signals with an appreciable signal-to-noise ratio were obtained by introducing nanogram amounts of the sample into the microplasma… mechanism. The portable fiber-optic spectrometer (StellarNet, Inc., FL) had a fixed entrance slit (25im), a focal length of 12 cm, and it was equipped with a 2048-pixel CCD detector and a 600-im-diameter fiber optic cable.