Highly oriented, free-standing, superconducting NbN films growth on chemical vapor deposited graphene

Saraswat, Garima; Pc, Gupta; Bhattacharya, Arnab; Raychaudhuri, Pratap

doi:10.1063/1.4875356

Cited by 8 publications

(6 citation statements)

References 27 publications

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“…larger diffusion constant / lower resistivity. Indeed, the resistivities ρ xx ∼ 60 µΩcm we observe are significantly lower than previously reported [10,26,27]. One should note, however, that the above formula yields B c2 (0) ∼ 2.5 T for our films, a significantly lower field than the value extracted from Fig.…”

Section: Analysis and Discussioncontrasting

confidence: 62%

“…The upper critical field B c2 is very similar for all of our films, but much lower than for other films with T c higher than 14 K reported in the literature [10,26,27]. In the dirty limit -defined by ℓ ≪ ξ(0) -B c2 (0) is related to resistivity and diffusion constant via B c2 (0) = 0.69T c 4k B /πeD = 0.69T c 4ek B N V ρ xx /π [28].…”

Section: Analysis and Discussionsupporting

confidence: 60%

See 1 more Smart Citation

Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

Hazra¹,

Tsavdaris²,

Jebari³

et al. 2016

Supercond. Sci. Technol.

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Niobium nitride (NbN) is widely used in high-frequency superconducting electronics circuits because it has one of the highest superconducting transition temperatures (Tc ∼ 16.5 K) and largest gap among conventional superconductors. In its thin-film form, the Tc of NbN is very sensitive to growth conditions and it still remains a challenge to grow NbN thin film (below 50 nm) with high Tc. Here, we report on the superconducting properties of NbN thin films grown by high-temperature chemical vapor deposition (HTCVD). Transport measurements reveal significantly lower disorder than previously reported, characterized by a Ioffe-Regel (kF ℓ) parameter of ∼ 14. Accordingly we observe Tc ∼ 17.06 K (point of 50 % of normal state resistance), the highest value reported so far for films of thickness below 50 nm, indicating that HTCVD could be particularly useful for growing high quality NbN thin films.Niobium nitride (NbN)thin films -thanks to their high T c ∼ 16.5 K, superconducting energy gap ∆ ∼ 2.5 meV, and upper critical field B c2 ∼ 40 T -have been the subject of intense research for the last few decades, both on application and fundamental grounds. The combination of high T c and small coherence length (ξ(0) ∼ 5 nm) allows one to fabricate very thin NbN films with reasonably high T c , which is essential for, e.g, Superconducting Single Photon Detectors (see e.g. [1,2]). NbN thin films are used as hot electron bolometers and superconducting radio frequency cavities. NbN has higher kinetic inductance to other S-wave superconductors [3], which this helps fabricating superconducting micro wave resonators with high characteristic impedance and microwave kinetic inductance detectors. On the fundamental level, the effects of disorder on superconducting and normal state properties have been studied in NbN thin films [4][5][6]. Nano-wires, made from NbN thin films, have demonstrated thermal and quantum phase slips [7]a phenomenon of great interest in understanding onedimensional superconductivity. Further, the large superconducting energy gap of NbN can be explored in designing circuit Quantum Electrodynamics experiments in the THz frequency range.Thus, there has been a growing demand of high quality NbN thin films. Reactive DC magnetron sputtering from an Nb target in an argon and nitrogen atmosphere is most commonly used to deposit NbN on various substrates [8][9][10]. The main difficulty in this process, arises from the creation of atomic level nitrogen vacancies and from the formation of non-superconducting Nb 2 N and hexagonal phases. Besides, in the optimal parameter range, the high sputtering rate (typically ∼ 1-5 nm/sec) makes it difficult to control the thickness below 10 nm. Some other methods, where the superconducting properties of NbN thin films were probed, include Pulsed Laser Deposition (PLD) [11,12], Molecular Beam Epitaxy (MBE) [13] and Atomic Layer Deposition (ALD) [14]. In this regard, de-position of superconducting NbN films by high temperature chemical vapor deposition (HTCVD) is rather rare. HTCVD, comp...

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Section: Analysis and Discussioncontrasting

confidence: 62%

Section: Analysis and Discussionsupporting

confidence: 60%

Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

Hazra¹,

Tsavdaris²,

Jebari³

et al. 2016

Supercond. Sci. Technol.

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show abstract

“…Primarily, dimensionality of a superconducting film on a dielectric substrate decreases with the decrease of the film thickness d. Dependences of the critical temperature on the thickness of superconducting films were intensively studied both experimentally and theoretically. It has been observed that in Nb [1,2], NbN [3,4,5], TaN [6], TiN [7], Pb [8], Bi [9], WSi [10] and other elementary and compound superconducting films critical temperatures decrease with the decrease in their thicknesses. It is well established that for films prepared by optimized technology and having thicknesses much larger than the coherence length the transition temperature TC is independent of the thickness and equals TC of corresponding bulk specimens.…”

Section: Introductionmentioning

confidence: 99%

Proximity effect model of ultranarrow NbN strips

et al. 2017

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We show that narrow superconducting strips in superconducting (S) and normal (N) states are universally described by the model presenting them as lateral NSN proximity systems in which the superconducting central band is sandwiched between damaged edge-bands with suppressed superconductivity. The width of the superconducting band was experimentally determined from the value of magnetic field at which the band transits from the Meissner state to the static vortex state. Systematic experimental study of 4.9 nm thick NbN strips with widths in the interval from 50 nm to 20 m, which are all smaller than the Pearl's length, demonstrates gradual evolution of the temperature dependence of the critical current with the change of the strip width.

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“…Free-standing films without solid substrates are very useful for achieving flexibility, selective formability, and large-scale applicability. − To demonstrate the flexibility and formability, a free-standing superconductor film was prepared as a new application of our proposed paste technology. The free-standing films were prepared by the method described above using NbN paste with a high T c .…”

Section: Experiments Results and Discussionmentioning

confidence: 99%

“…The proposed technology is also fundamental for fabricating flexible superconducting free-standing films. This technology is expected to be useful for creating superconducting connections ,− that maintain both superconductivity and mechanical links between wires and thin films and for superconducting interconnect technology in multilayered devices that electrically and mechanically connect the upper and lower layers, − which can act as adhesives with superconducting properties.…”

Section: Experiments Results and Discussionmentioning

confidence: 99%

Superconducting Flexible Organic/Inorganic Hybrid Compound Adhesives

2022

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Superconducting pastes have been successfully developed from superconducting particles using conventional methods, thereby opening up new avenues for the application of superconducting materials. These pastes are isotropic one-component heat-curable adhesives belonging to the class of organic/inorganic hybrid compounds. In this work, superconducting pastes prepared using Nb or NbN superconducting particles are applied to solid substrates through screen printing and then heat-cured under optimized conditions to form single-phase thick films. The resistivity of the Nb and NbN films becomes zero at 7.2 and 10.5 K, respectively, indicating that both these films are superconductive at cryogenic temperatures. A large free-standing film of length approximately 130 mm is successfully developed using the NbN paste. The free-standing film is flexible and exhibits superconductivity at 11 K. These results demonstrate, for the first time, that superconductivity, flexibility, adhesion, and ink properties can be simultaneously achieved in organic/inorganic hybrid compounds.

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Highly oriented, free-standing, superconducting NbN films growth on chemical vapor deposited graphene

Cited by 8 publications

References 27 publications

Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

Superconducting properties of very high quality NbN thin films grown by high temperature chemical vapor deposition

Proximity effect model of ultranarrow NbN strips

Superconducting Flexible Organic/Inorganic Hybrid Compound Adhesives

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