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We present characterization results of microscopic platinum wires as bolometers. The wire lengths range from 16 μm down to 300 nm. Thus they are in many cases significantly smaller in size than the wavelength of the radiation from the 1200 K blackbody source they were exposed to. We observe a steep rise in both responsivity ℜ and detectivity D* with decreasing wire size, reaching ℜ = 3.1×10(4) V/W and D* = 2.7×10(9) cm Hz(1/2)/W at room temperature for a 300×300 nm(2) device. Two significant advantages of such small wires as bolometers are their low power requirement and fast response time. Our numerical estimations suggest response times in the order of nanoseconds for the smallest samples. They could help improve resolution and response of thermal imaging devices, for example. We believe the performance may be further improved by optimizing the design and operating parameters.

This paper presents how reducing the width and length of a bolometer’s sensing core affects its performance. Bolometer devices made of thin films of platinum with various lateral dimensions—widths ranging from 300 nm to 4 μm and lengths ranging from 300 nm to 19 μm were tested. Some are significantly smaller in size than the wavelengths they are exposed to, coming from a blackbody source with a λpeak of 2.74 μm. A resonance effect is revealed for samples of specific dimensions, where the performance is enhanced. Further, a strong increase in responsivity appears when the sample’s width is narrowed, whereas specific detectivity remains independent of any change in dimensions. We believe that some of these features are due to plasmonic effects, which may explain the high performance reached by smaller samples. It seems that graphene could be subject to similar geometrical effects to our thin-film bolometers. [ABSTRACT FROM AUTHOR]