Superconductivity in epitaxial InN thin films with large critical fields

Experimental evidence of a very thin superconducting layer in epitaxial indium nitride

“…The cryostat used for these measurements was a sorption pumped He-3 system, where base temperature ≈250 mK could be reached. Preliminary observations of large critical fields and quasi-2D behaviour were reported earlier [22]. Due to the absence of Schottky barrier at the surface of InN (similar to InAs) ohmic contacts did not require any annealing.…”

“…For PA-MBE samples, first a buffer layer of GaN was deposited on sapphire substrate and then InN was grown on GaN using PA-MBE system [21]. The role of various growth parameters, structural studies, cross-sectional analysis, epitaxial relationships between the film and the substrate, width of the transitions etc have been reported by us in [19,21] and [22]. We note that the absence of oxygen O1s core level transition in XPS (and hence negligible oxygen impurity) was also demonstrated for the PA-MBE samples in [21].…”

“…T c0 is the mean-field transition temperature. The details of the growth methods (CVD and PA-MBE paramters like gas flow rates, substrate temperatures etc) and structural studies have been reported earlier in [19][20][21][22] and are not repeated here. The thicknesses reported here are the targeted thicknesses during the growth process.…”