Study on the Temperature Dependency Effect of Thermal Coefficient of Resistance in Amorphous Silicon for Uncooled Microbolometer Application

MRS Advances ◽  
2019 ◽  
Vol 4 (08) ◽  
pp. 447-455
Author(s):  
Junkyo Jeong ◽  
Byeongjun Jeong ◽  
Jaeseop Oh ◽  
Gawon Lee
Keyword(s):  
Amorphous Silicon ◽  
Joule Heating ◽  
Operating Temperature ◽  
Effect Of Temperature ◽  
Thermal Coefficient ◽  
Temperature Dependency ◽  
Ir Radiation ◽  
Absolute Value ◽  
Uncooled Microbolometer ◽  
Thermal Coefficient Of Resistance

ABSTRACTIn this paper, we studied the temperature dependency effect of thermal coefficient of resistance (TCR) in amorphous silicon (a-Si) on the properties of uncooled microbolometer with a-Si as a resistance layer by simulation. The temperature of the microbolometer rises during the operation mainly due to the heat generated by Joule heating as well as IR radiation. Generally, the TCR of a-Si is treated as a constant for the simplicity but the absolute value of TCR has been reported to decrease as the temperature increases. Therefore, to improve the device characteristics, the effect of temperature dependency of TCR in a-Si should be considered carefully in the range of the operating temperature. The responsivities of microbolometer are simulated according to the width of the resistance layer (W) with TCR as a function of temperature, which shows that the optimal W condition is affected by the TCR value changed by the temperature.

A Boron Doped Amorphous Silicon Thin-Film Bolometer for Long Wavelength Detection

2002 ◽  
Vol 744 ◽  
Author(s):  
A. Heredia-J ◽  
A. Torres-J ◽  
A. Jaramillo-N ◽  
F.J. De la Hidalga-W ◽  
M. Landa-V.
Keyword(s):  
Thin Film ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Thermal Coefficient ◽  
Silicon Thin Film ◽  
Long Wavelength ◽  
Silicon Nitride Membrane ◽  
Boron Doped ◽  
Wavelength Detection ◽  
Thermal Coefficient Of Resistance

ABSTRACTThe fabrication of a bolometer for infrared detection using a boron doped amorphous silicon (a-Si-B:H) thin film is presented for the first time. This thin film (170 nm) was deposited on a silicon nitride membrane sustained by a frame made of micromachined crystalline silicon in order to improve the thermal isolation. Electrical connectivity to the element was achieved by means of aluminum contact pads. The resultant figures of merit, measured at room temperature, were: electrical conductivity of 1.513×10-3 (Ω-cm)-1, thermal coefficient of resistance of 3.4 %K-1, and the device is sensitive to temperature variations as small as 20 mK.

Exploring the infrared-sensing properties of polymorphous silicon-germanium (pm-SixGey:H) thin films

2014 ◽  
Vol 92 (7/8) ◽  
pp. 565-569 ◽  
Author(s):  
M. Moreno ◽  
A. Torres ◽  
C. Calleja ◽  
R. Ambrosio ◽  
P. Rosales ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Germanium ◽  
Infrared Detection ◽  
Thermal Coefficient ◽  
Ir Radiation ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Sensing Properties ◽  
Infrared Sensing ◽  
Thermal Coefficient Of Resistance

In this work we have performed an exploratory study of the infrared (IR) sensing properties of polymorphous silicon–germanium (pm-SixGey:H) thin films. Our objective was to study the characteristics that are important parameters for infrared detection, as activation energy (Ea), thermal coefficient of resistance (TCR), room temperature conductivity (σRT), and responsivity to IR radiation. After characterization, our results demonstrated that pm-SiGe:H films have advantages over a-Si:H,B, pm-Si:H, and pm-Ge:H, because of the possibility to tailor its properties as σRT, Ea, and TCR, and moreover, the possibility to adjust those values for specific applications.

scholarly journals Amorphous Silicon-Germanium Films with Embedded Nanocrystals for Thermal Detectors with Very High Sensitivity

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Cesar Calleja ◽  
Alfonso Torres ◽  
Pedro Rosales-Quintero ◽  
Mario Moreno
Keyword(s):  
Amorphous Silicon ◽  
Silicon Germanium ◽  
Chemical Vapor ◽  
Focal Plane Arrays ◽  
Large Temperature ◽  
Thermal Coefficient ◽  
Thermal Detectors ◽  
Germanium Films ◽  
Amorphous Silicon Germanium ◽  
Very High

We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nanocrystals in a plasma enhanced chemical vapor deposition (PECVD) reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR), which is a signature of the sensitivity in thermal detectors (microbolometers). Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9% K−1). Our results show that amorphous silicon-germanium films with embedded nanocrystals can be used as thermosensitive films in high performance infrared focal plane arrays (IRFPAs) used in commercial thermal cameras.

Effect of temperature on quantifying glycated (glycosylated) hemoglobin by cation-exchange chromatography.

1985 ◽  
Vol 31 (1) ◽  
pp. 114-117 ◽  
Author(s):  
R Flückiger ◽  
T Woodtli
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
High Performance ◽  
Glycated Hemoglobin ◽  
Operating Temperature ◽  
Glycosylated Hemoglobin ◽  
Regression Line ◽  
Exchange Chromatography ◽  
Effect Of Temperature ◽  
Cation Exchange Chromatography

Abstract As a consequence of nonideal chromatographic conditions, values for stable glycated hemoglobin (HbA1c) determined by cation-exchange chromatography in a commercial minicolumn system (y) or by "high-performance" liquid chromatography (x) differ markedly, yielding the regression line y = 0.82x + 0.6. With use of the protocol specified by the manufacturer, 20% of the HbA1c peak is not collected in the HbA1c fraction. Increasing the ionic strength of the eluting buffer by increasing the operating temperature to 28 degrees C increases the rate of elution from the minicolumn, making results of the two methods more closely comparable (y = 0.98x - 0.22). Because at a given pH the elution volume is determined primarily by the ionic strength, close limits on the composition of the eluting buffer are set by the temperature-dependence of its ionic strength. At a specified temperature and pH the position of a peak can be judged to within a volume of 1 mL if the conductivity of the eluent does not vary by more than +/- 0.05 mS.

Temperature dependency of force loss and Ca2+homeostasis in mouse EDL muscle after eccentric contractions

2002 ◽  
Vol 282 (4) ◽  
pp. R1122-R1132 ◽  
Author(s):  
Gordon L. Warren ◽  
Christopher P. Ingalls ◽  
R. B. Armstrong
Keyword(s):  
Isometric Force ◽  
Membrane Integrity ◽  
Significant Loss ◽  
Eccentric Contractions ◽  
Effect Of Temperature ◽  
Temperature Dependency ◽  
Bathing Medium ◽  
Cell Membrane Integrity ◽  
Temperature Loss ◽  
Ldh Release

The goals of this study were first to determine the effect of temperature on the force loss that results from eccentric contractions in mouse extensor digitorum longus (EDL) muscles and then to evaluate a potential role for altered Ca2+ homeostasis explaining the greater isometric force loss observed at the higher temperatures. Isolated muscles performed five eccentric or five isometric contractions at either 15, 20, 25, 30, 33.5, or 37°C. Isometric force loss, caffeine-induced force, lactate dehydrogenase (LDH) release, muscle accumulation of 45Ca2+ from the bathing medium, sarcoplasmic reticulum (SR) Ca2+ uptake, and resting muscle fiber free cytosolic Ca2+ concentration ([Ca2+]i) were measured. The isometric force loss after eccentric contractions increased progressively as temperature rose; at 15°C, there was no significant loss of force, but at 37°C, there was a 30–39% loss of force. After eccentric contractions, caffeine-induced force was not affected by temperature nor was it different from that of control muscles at any temperature. Loss of cell membrane integrity and subsequent influx of extracellular Ca2+ as indicated by LDH release and muscle45Ca2+ accumulation, respectively, were minimal over the 15–25°C range, but both increased as an exponential function of temperature between 30 and 37°C. SR Ca2+uptake showed no impairment as temperature increased, and the eccentric contraction-induced rise in resting fiber [Ca2+]i was unaffected by temperature over the 15–25°C range. In conclusion, the isometric force loss after eccentric contractions is temperature dependent, but the temperature dependency does not appear to be readily explainable by alterations in Ca2+ homeostasis.

scholarly journals Vertically Aligned Few-Layered Graphene-Based Non-Cryogenic Bolometer

2019 ◽  
Vol 5 (2) ◽  
pp. 23 ◽  
Author(s):  
Anil K. Yadav ◽  
Saba Mehsar Khan ◽  
Anirban Kundu ◽  
Renu Rani ◽  
Navneet Soin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Thermal Coefficient ◽  
Carbon Nanomaterial ◽  
Electrical Switching ◽  
Current Voltage ◽  
Infra Red ◽  
Vertically Aligned ◽  
Thermal Coefficient Of Resistance ◽  
Probe Measurements ◽  
Bolometric Effect

In this study, we report the photoresponse of vertically aligned few-layered graphene (VAG) upon infra-red (IR) irradiation at room temperature. Four probe measurements showed the current–voltage (I–V) characteristic of electrical switching during pulsed IR irradiation. The photoresponse reported here for VAG was significantly higher than that reported for carbon nanotube (CNT) samples. Our investigation shows that such a photoresponse arose solely from the bolometric effect, where the conductivity changed with temperature. The resistance magnitude of the VAGs increased ~two fold for each 6 °C increase in temperature. Also, the Thermal Coefficient of Resistance (TCR) in this region was ~11%/K, which is the highest TCR value reported for any carbon nanomaterial.

LETI/LIR's amorphous silicon uncooled microbolometer development

1998 ◽  
Author(s):  
Jean-Luc Tissot ◽  
Frederic Rothan ◽  
Corrinne Vedel ◽  
Michel Vilain ◽  
Jean-Jacques Yon
Keyword(s):  
Amorphous Silicon ◽  
Uncooled Microbolometer
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