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

5th International Conference of Photonics and Information Optics

Seleznev, V.A.^1,2 ; Divochiy, A.V.^1,2 ; Vakhtomin, Yu B^1,2 ; Morozov, P.V.^2 ; Zolotov, P.I.^1,2 ; Vasil'Ev, D.D.^3 ; Moiseev, K.M.^3 ; Malevannaya, E.I.^3 ; Smirnov, K.V.^1,2,4

Moscow State Pedagogical University, Moscow

119435, Russia^1

CJSC Superconducting Nanotechnology (Scontel), Moscow

119021, Russia^2

Bauman Moscow State Technical University, Moscow

105005, Russia^3

National Research University Higher School of Economics, Moscow

101000, Russia^4

关键词: Deposition technology;    High critical temperature;    Noise equivalent power;    Single-photon detectors;    Superconducting detector;    Superconducting single-photon detectors;    Superconducting structure;    Superconducting transitions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/737/1/012032/pdf
DOI  :  10.1088/1742-6596/737/1/012032

来源: IOP

【 摘 要 】

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 (Ib) 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-1limited 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).