Epitaxial growth of ultra-thin NbN films on AlxGa1-xN buffer-layers
Artikel i vetenskaplig tidskrift, 2014

The suitability of AlxGa1-xN epi-layer to deposit onto ultra-thin NbN films has been demonstrated for the first time. High quality single-crystal films with 5 nm thickness confirmed by high-resolution transmission electron microscopy (HRTEM) have been deposited in a reproducible manner by means of reactive DC magnetron sputtering at elevated temperatures and exhibit critical temperatures (Tc) as high as 13.2 K and residual resistivity ratio (RRR) ~ 1 on hexagonal GaN epi-layer. With increasing the Al-content x in the AlxGa1-xN epi-layer above 20% a gradual deterioration of Tc down to 10 K was observed. Deposition of NbN on bare silicon substrates served as reference and comparison. Excellent spatial homogeneity of the fabricated films was confirmed by R(T) measurements of patterned micro-bridges across the entire film area. The superconducting properties of those films were further characterized by critical magnetic field and critical current measurements. It is expected that the employment of GaN material as a buffer-layer for the deposition of ultra-thin NbN films prospectively benefit terahertz electronics, particularly hot electron bolometer (HEB) mixers.

ultra-thin film

NbN

HEB

Författare

Sascha Krause

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Denis Meledin

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Vincent Desmaris

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Alexey Pavolotskiy

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Victor Belitsky

Chalmers, Rymd- och geovetenskap, Avancerad mottagarutveckling

Mariusz Rudzinski

Instytutu Technologii Materialow Elektronicznych w Warszawie

E. Pippel

Max Planck-institutet

Superconductor Science and Technology

0953-2048 (ISSN) 1361-6668 (eISSN)

Vol. 27 6 065009

Styrkeområden

Nanovetenskap och nanoteknik

Ämneskategorier

Nanoteknik

DOI

10.1088/0953-2048/27/6/065009