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Статья

Superconducting detector of IR single-photons based on thin WSi films

Journal of Physics: Conference Series. 2016. Vol. 737. No. 1. P. 012032.
Seleznev V., Divochiy A., Vakhtomin Y., Morozov P., Zolotov P., Vasil'Ev D., Moiseev K., Malevannaya E., Smirnov K.

We have developed the deposition technology of WSi thin films 4 to 9 nm thick with high temperature values of superconducting transition (Tc∼4 K). Based on deposed films there were produced nanostructures with indicative planar sizes ∼100 nm, and the research revealed that even on nanoscale the films possess of high critical temperature values of the superconducting transition (Tc∼3.3-3.7 K) which certifies high quality and homogeneity of the films created. The first experiments on creating superconducting single-photon detectors showed that the detectors' SDE (system detection efficiency) with increasing bias current (I b) reaches a constant value of ∼30% (for X=1.55 micron) defined by infrared radiation absorption by the superconducting structure. To enhance radiation absorption by the superconductor there were created detectors with cavity structures which demonstrated a practically constant value of quantum efficiency >65% for bias currents Ib>0.6-Ic. The minimal dark counts level (DC) made 1 s-1 limited with background noise. Hence WSi is the most promising material for creating single-photon detectors with record SDE/DC ratio and noise equivalent power (NEP).