Details

Autor(en) / Beteiligte

• Roch, T.
• Gregor, M.
• Volkov, S.
• Čaplovičová, M.
• Satrapinskyy, L.
• Plecenik, A.

Titel

Substrate dependent epitaxy of superconducting niobium nitride thin films grown by pulsed laser deposition

Ist Teil von

• Applied surface science, 2021-06, Vol.551, p.149333, Article 149333

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• [Display omitted] •δ-NbN films grown by pulsed laser deposition on Si,MgO, R- and C-Al2O3 substrates.•For Si the film is random polycrystalline and for MgO it shows cube on cube epitaxy.•For R-Al2O3 the film grains grow along [135] axis and show strong twinning.•Highest quality film with largest crystallites and best epitaxy NbN(111)||C-Al2O3(0001).•Partly relaxed layers show 2–3 nm thin interdiffused interlayer at the substrate interface. Niobium nitride (NbN) has suitable mechanical properties for application as protective coatings in mechanical engineering, and also its superconductivity can be utilized in thin film devices for sensorics or in combination with ferromagnet in spintronics. Long-range superconducting proximity effect at the heterostructures with a weak ferromagnet can be used for generation of spin-polarized current. For any operational heterostructure application the high quality NbN thin films need to be prepared. In this work we have investigated impact of the substrates on the structure and preferential orientation of niobium nitride thin films fabricated by pulsed laser deposition at 600 °C on Si (001), MgO (001), C-plane and R-plane Al2O3 substrates. Growth parameters have been tuned in order to obtain single superconducting δ-NbN phase. Microstructure was analyzed by X-ray diffraction and transmission electron microscopy. Si substrate does not induce the film preferential orientation. Films on MgO are epitaxial (001) oriented. Films on R-Al2O3 show (135) orientation with twinned crystallites on the lower symmetry substrate surface. The (111) epitaxial growth with the largest crystallites and their smallest tilting was achieved on C-Al2O3 substrate leading to the best superconducting properties.