TY - JOUR
T1 - Correlation between thickness dependent nanoscale structural chemistry and superconducting properties of ultrathin epitaxial NbN films
AU - Licata, Olivia G.
AU - Sarker, Jith
AU - Bachhav, Mukesh
AU - Roy, Pinku
AU - Wei, Xiucheng
AU - Yang, Zihao
AU - Patibandla, Nag
AU - Zeng, Hao
AU - Zhu, Mingwei
AU - Jia, Quanxi
AU - Mazumder, Baishakhi
N1 - Funding Information:
The work at University at Buffalo ( UB ) was partially supported by both the SUNY Applied Materials Research Institute (SAMRI), a strategic alliance between the State University of New York ( SUNY ) and Applied Materials , Inc. Licata, Sarker and Mazumder acknowledge support from the University at Buffalo Quantum Initiative Grant. Bachhav acknowledges support from Laboratory Directed Research & Development ( LDRD ) Program under the Department of Energy ( DOE ), Office of Nuclear Energy under DOE Idaho Operations Office Contract DE-AC07-05ID14517. The authors also acknowledge the support of the Irradiated Materials Characterization Laboratory (IMCL) staff members at Idaho National Lab ( INL ) for the use of FIB and APT tool.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/4/15
Y1 - 2022/4/15
N2 - NbN-based superconductors have attracted interest for superconducting circuits, quantum computation and high frequency devices. The superconducting properties of NbN films are predominately reliant on the microstructure, therefore, an atomic-level understanding of the structure-chemistry is required to achieve high quality epitaxial NbN films. Here, the thickness-dependent superconducting properties of NbN films (5, 10, and 50 nm) within NbN/AlN/Al2O3 heterostructures are investigated. NbN and AlN were epitaxially grown by an industrial scale physical vapor deposition technique. The role of nanoscale chemistry on the ultrathin NbN superconducting film is investigated at the atomic level for the first time via atom probe tomography, providing three-dimensional atomic distribution, chemical homogeneity, effect of impurities, specially, in secondary phase formations and interfacial abruptness. The NbN film with 5 nm of thickness demonstrates a superconducting transition temperature of 11.2 K as compared to 50 nm NbN films with a transition temperature of 15.3 K. These thickness dependent variation of superconducting properties are associated with the chemical inhomogeneity in terms of in-plane N:Nb distribution, secondary phase formations and NbN/AlN interfacial abruptness as a function of the NbN films thicknesses. The analysis depicts the interplay between the surface/interface and the superconducting properties of ultrathin NbN films. These results provide insights on material design and growth that will enable the development of optimized superconducting NbN films for quantum devices.
AB - NbN-based superconductors have attracted interest for superconducting circuits, quantum computation and high frequency devices. The superconducting properties of NbN films are predominately reliant on the microstructure, therefore, an atomic-level understanding of the structure-chemistry is required to achieve high quality epitaxial NbN films. Here, the thickness-dependent superconducting properties of NbN films (5, 10, and 50 nm) within NbN/AlN/Al2O3 heterostructures are investigated. NbN and AlN were epitaxially grown by an industrial scale physical vapor deposition technique. The role of nanoscale chemistry on the ultrathin NbN superconducting film is investigated at the atomic level for the first time via atom probe tomography, providing three-dimensional atomic distribution, chemical homogeneity, effect of impurities, specially, in secondary phase formations and interfacial abruptness. The NbN film with 5 nm of thickness demonstrates a superconducting transition temperature of 11.2 K as compared to 50 nm NbN films with a transition temperature of 15.3 K. These thickness dependent variation of superconducting properties are associated with the chemical inhomogeneity in terms of in-plane N:Nb distribution, secondary phase formations and NbN/AlN interfacial abruptness as a function of the NbN films thicknesses. The analysis depicts the interplay between the surface/interface and the superconducting properties of ultrathin NbN films. These results provide insights on material design and growth that will enable the development of optimized superconducting NbN films for quantum devices.
KW - Atom probe tomography
KW - Compositional inhomogeneity
KW - Epitaxy
KW - Nitride superconductor
KW - Thin films
UR - https://www.scopus.com/pages/publications/85125529601
UR - https://www.mendeley.com/catalogue/15a46e27-8de8-32c6-ae1e-c6e54a77ec2a/
U2 - 10.1016/j.matchemphys.2022.125962
DO - 10.1016/j.matchemphys.2022.125962
M3 - Article
AN - SCOPUS:85125529601
SN - 0254-0584
VL - 282
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
M1 - 125962
ER -