Single-crystalline Bi2Sr2CaCu2O8+x detectors for direct detection of microwave radiation

Journal article, 2015

We test radiation detectors made from single-crystalline Bi2Sr2CaCu2O8+x flakes put on oxidized Si substrates. The 100-nm-thick flakes are lithographically patterned into 4 x 12 mu m(2) large rectangles embedded in thin-film log-spiral antennas. The SiO2 layer weakens the thermal link between the flakes and the bath. Two modes of radiation detection have been observed. For a bolometric type of sensors a responsivity of similar to 300 V/W and a noise equivalent power of 30 nW/root Hz has been deduced at 70 K. Much more sensitive is the non-bolometric device showing characteristics similar to a Golay-type detector while being at least a thousand times faster. Making smaller (sub-mu m) structures is expected to significantly improve the performance of these devices and makes them very competitive among other microwave and terahertz detectors.