Performance of GaAs microbridge thermocouple infrared detectors |
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Authors: | Nui Chong Srinivas TAS Ahmed H |
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Affiliation: | Dept. of Phys., Cambridge Univ.; |
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Abstract: | GaAs microbridge thermocouples with lengths ranging from 40 to 650 μm and operating at room temperature have been fabricated for the detection of infrared radiation. A CO2 laser of a 10.6 μm wavelength was used to characterize the performance of the detectors in air and in vacuum. A responsivity of 4.2 V/W with a corresponding detectivity D*=8×106 cm Hz1/2/W and a time constant of 2.2 ms have been measured in vacuum for 650-μm-long bridges, and a shorter time constant of 50 μs was obtained for 40-μm-long bridges. An analytic thermal transport model has been used to simulate the operation of the sensors. The heat-transfer coefficient has been evaluated by comparing the data from air and vacuum measurements. The spectral response and the absorbance of the microbridge have also been presented |
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