Header

UZH-Logo

Maintenance Infos

Characteristics of superconducting tungsten silicide $W_{x}Si_{1−x}$ for single photon detection


Zhang, X; Engel, A; Wang, Q; Schilling, A; Semenov, A; Sidorova, M; Hübers, H-W; Charaev, I; Ilin, K; Siegel, M (2016). Characteristics of superconducting tungsten silicide $W_{x}Si_{1−x}$ for single photon detection. Physical Review B, 94(17):174509.

Abstract

Superconducting properties of three series of amorphous $W_{x}Si_{1−x}$ films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous $W_{x}Si_{1−x}$ films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick $W_{0.85}Si_{0.15}$ film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles.

Abstract

Superconducting properties of three series of amorphous $W_{x}Si_{1−x}$ films with different thickness and stoichiometry were investigated by dc transport measurements in a magnetic field up to 9 T. These amorphous $W_{x}Si_{1−x}$ films were deposited by magnetron cosputtering of the elemental source targets onto silicon substrates at room temperature and patterned in the form of bridges by optical lithography and reactive ion etching. Analysis of the data on magnetoconductivity allowed us to extract the critical temperatures, superconducting coherence lengths, magnetic penetration depths, and diffusion constants of electrons in the normal state as functions of film thickness for each stoichiometry. Two basic time constants were derived from transport and time-resolving measurements. A dynamic process of the formation of a hotspot was analyzed in the framework of a diffusion-based vortex-entry model. We used a two-stage diffusion approach and defined a hotspot size by assuming that the quasiparticles and normal-state electrons have the same diffusion constant. With this definition and these measured material parameters, the hotspot in the 5-nm-thick $W_{0.85}Si_{0.15}$ film had a diameter of 107 nm at the peak of the number of nonequilibrium quasiparticles.

Statistics

Citations

Altmetrics

Downloads

14 downloads since deposited on 11 Jan 2017
14 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Language:English
Date:2016
Deposited On:11 Jan 2017 17:33
Last Modified:11 Jan 2017 17:33
Publisher:American Physical Society
ISSN:2469-9950
Publisher DOI:https://doi.org/10.1103/PhysRevB.94.174509

Download

Preview Icon on Download
Preview
Content: Accepted Version
Filetype: PDF
Size: 1MB
View at publisher
Preview Icon on Download
Preview
Content: Published Version
Filetype: PDF
Size: 1MB