| 1. |
- Andersson, Henrik, et al.
(författare)
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Processing and Characterization of a MOS Type Tetra Lateral Position Sensitive Detector with Indium Tin Oxide Gate Contact
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:9-10, s. 1704-1709
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Tidskriftsartikel (refereegranskat)abstract
- A 2-D tetra lateral position sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) principle has been manufactured and characterized. The active area of the device is 5 nun x 5 mm and the intention is to use the central 4 nun x 4 nun for low nonlinearity measurements. The gate contact is made of indium tin oxide (ITO) that is a degenerate electrically conducting semiconductor, which, in addition, is also transparent in the visible part of the spectrum. The use of a MOS structure results in a processing with no necessity to use implantation or diffusion in order to make the resistive p-layer as in a conventional p-n junction lateral effect PSD. Position measurements show good linearity in the middle 4 nun x 4 mm area. Within the middle 2.1 mm x 2.1 mm, the nonlinearity is within 1.7% of the active area with a position detection error of maximum 60 mu m. Measured MOS IV characteristics are compared to a level 3 spice model fit and show good agreement. The threshold voltage is determined to be -0.03 V. Responsivity measurements show a high sensitivity in the visible spectral region.
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| 2. |
- Aroutiounian, Vladimir M., et al.
(författare)
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Noise spectroscopy of gas sensors
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:5-6, s. 786-790
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Tidskriftsartikel (refereegranskat)abstract
- We study current-voltages and low-frequency noise characteristics of the metal-porous silicon-silicon single crystal-metal structure with 50% and 73% porosity of porous silicon. The study is performed in dry air and in a mix of dry air with carbon monoxide of different concentrations. The Hooge noise parameter alpha(H) and the parameter gamma in the frequency dependence of the noise voltage spectral density S-U (f) were determined from experimental data. High sensitivity of spectral dependence of noise to gas concentration allows offering powerful method for determination of gas concentration in the air or environment.
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| 3. |
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| 4. |
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| 5. |
- Jason, Johan, et al.
(författare)
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Experimental Study of an Intensity Modulated Fiber-Optic Position Sensor with a Novel Readout System
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:7, s. 1105-1113
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Tidskriftsartikel (refereegranskat)abstract
- An intensity modulated fiber-optic position sensor, based on a fiber to bundle coupling and a readout system using a CMOS image camera together with fast routines for position extraction and calibration, is experimentally demonstrated. Further a simulation of the complete sensor system setup is made, and possible sources of error are analyzed experimentally. Our analysis indicates the theoretical limit of the system and identifies the causes of system errors. The results are encouraging for further development of the system setup.
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| 6. |
- Jiang, M., et al.
(författare)
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Multiplexing scheme for self-interfering long-period fiber gratings using a low-coherence reflectometry
- 2007
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Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 7:11-12, s. 1663-1667
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Tidskriftsartikel (refereegranskat)abstract
- A novel multiplexing scheme based on a low-coherence reflectometry (LCR) is proposed for a sensing array (in parallel) of self-interfering long-period fiber gratings (SI-LPGs). Each SI-LPG sensor consists of an LPG and a section of fiber with a highly reflective end (mirror). The spectral information of each LPG is sensitive to some parameters of the surrounding measurand and can be reconstructed from the corresponding subreflectograms (obtained by the LCR) through a fast Fourier transformation. The sensing signals of multiple SI-LPG sensors can be multiplexed if the length of the fiber section in each sensor is set to a different value. Experiments of measuring the surrounding temperature at different sensors are demonstrated to show the good performance of our multiplexing system.
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| 7. |
- Kaestner, Anders P., et al.
(författare)
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Microwave polarimetry tomography of wood
- 2005
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Ingår i: IEEE Sensors Journal. - New York : IEEE Sensors Council. - 1530-437X .- 1558-1748. ; 5:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a new microwave-based method to make images of fiber structure, e.g., to locate knots in wood. Evaluation of Maxwell's equations for an electromagnetic wave propagating in an anisotropic media (wood) shows that the polarization of the wave depends on the local fiber orientation in the sample. Experiments support the theoretical evaluation showing that knots can be followed in images of polarimetric parameters, reconstructed from multiple monostatic measurements. The equipment works at low intensity and is, therefore, virtually harmless to human beings; furthermore, it can be made portable and be operated by a single person.
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| 8. |
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| 9. |
- Klingvall, Roger, et al.
(författare)
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Sub ppm detection of hydrogen
- 2008
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:03-Apr, s. 301-307
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Tidskriftsartikel (refereegranskat)abstract
- A light pulse technique and a field-effect device were used to detect small concentration steps of hydrogen in air. The detection limit was lower than 40 ppb, which is at least one order of magnitude lower than previously reported measurements (with field-effect devices) of hydrogen concentration in air. The device structure was a metal-insulator-semiconductor capacitor with a metal double layer with 17.5 nm Pd (upper layer) and 7.5 nm Pt on a SiO2 insulator and a Si substrate.
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| 10. |
- Klingvall, Roger, et al.
(författare)
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UV-SLPT for gas sensor research on MISiC devices
- 2007
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Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 7:03-Apr, s. 592-599
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Tidskriftsartikel (refereegranskat)abstract
- A modified Scanning Light Pulse Technique (SLPT) setup that can be used to evaluate SiC-based gas-sensitive field-effect devices is introduced. This is exemplified with measurements on a Pt-MISiC capacitor that has a metal thickness gradient. The device shows large responses to hydrogen and ammonia in air. The H-2 and NH3 responses show a complementary dependence on the Pt film thickness at 140 degrees C. The temperature dependence differs however for the two gases. The measurement setup uses UV transparent optics together with mechanical chopping of light from a short wavelength light source. The spatial resolution of the system is found to be approximately 50 mu m.
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