Large-area microwire MoSi single-photon detectors at 1550 nm wavelength

• Published in: Applied physics letters Vol. 116; no. 24
• Main Authors: Charaev, I., Morimoto, Y., Dane, A., Agarwal, A., Colangelo, M., Berggren, K. K.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15-06-2020
• Subjects: Applied physics; Detectors; Nanowires; Order parameters; Photons; Resistors; Sensors; Superconductivity; Thick films
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0005439

We demonstrate saturated internal detection efficiency at 1550 nm wavelengths for meander-shaped superconducting nanowire single-photon detectors made of 3 nm thick MoSi films with widths of 1 and 3 μm and active areas up to 400 × 400 μm2. Despite hairpin turns and a large number of squares (up to 104) in the device, the dark count rate was measured to be ∼103 cps at 99% of the switching current. This value is about two orders of magnitude lower than the results reported recently for short MoSi devices with shunt resistors. We also found that 5 nm thick MoSi detectors with the same geometry were insensitive to single near-infrared photons, which may be associated with different levels of suppression of the superconducting order parameter. However, our results obtained on 3 nm thick MoSi devices are in good agreement with predictions in the frame of a kinetic-equation approach.