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Regular version of the site

Article

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

Journal of Physics: Conference Series. 2016. Vol. 737. No. 012032. P. 1-9.
Seleznev V., Divochiy A., Vakhtomin Y., Morozov P., Золотов Ф. И., 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 К) 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 (Ib) reaches a constant value of ~30% (for =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).