Dense rotational twins in superconducting (111)-orientated δ-NbN epitaxial films on 4H-SiC substrates
Open Access
- 4 February 2021
- journal article
- research article
- Published by IOP Publishing in Superconductor Science and Technology
- Vol. 34 (4), 045019
- https://doi.org/10.1088/1361-6668/abe360
Abstract
In order to confirm the superconductivity observed in hexagonal ϵ-NbN reported recently, we have deposited NbN film on (0001) 4H-SiC substrate, with good lattice match, intentionally to grow hexagonal NbN phase. The detailed structural analysis show that the deposited films are (111)-orientated δ-NbN phase with dense rotational (60°) twins. Double diffraction effect in selected area electron diffraction and Moiré fringes in high resolution transmission electron microscope images confirm the existence of rotational twins in nanometer scale. The growth of highly twined film results from no energy preference for the two rotational twins of (111)-orientated δ-NbN to bond with the Si-faced (0001) 4H-SiC substrate. These highly twined δ-NbN epitaxial films exhibit high normal state resistivity, lower T C, but good spatial uniformity of superconducting energy gap. No ϵ-NbN phase was observed in this study which is might due to a low growth temperature of thin film.Keywords
This publication has 57 references indexed in Scilit:
- NbN superconducting nanowire single-photon detector with an active area of 300 μm-in-diameterAIP Advances, 2019
- Investigation of the Performance of an Ultralow-Dark-Count Superconducting Nanowire Single-Photon DetectorJapanese Journal of Applied Physics, 2013
- Niobium nitride-based normal metal-insulator-superconductor tunnel junction microthermometerApplied Physics Letters, 2013
- Sensitivity and gigahertz counting performance of NbN superconducting single-photon detectorsApplied Physics Letters, 2004
- Detection efficiency of large-active-area NbN single-photon superconducting detectors in the ultraviolet to near-infrared rangeApplied Physics Letters, 2002
- Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an atomic force microscopePhysica C: Superconductivity and its Applications, 2002
- Internally shunted sputtered NbN Josephson junctions with a TaNx barrier for nonlatching logic applicationsApplied Physics Letters, 2001
- High critical current density NbN/AlN/NbN tunnel junctions fabricated on ambient temperature MgO substratesApplied Physics Letters, 1994
- Niobium nitride Josephson tunnel junctions with magnesium oxide barriersApplied Physics Letters, 1985
- Superconducting Transition Temperatures of R. F. Sputtered NbN FilmsJapanese Journal of Applied Physics, 1971