ABSTRACTWe have deposited thin films of the electron-doped, high temperature superconductor Nd1.85Ce0.15CuO4−y by pulsed laser deposition. Films were deposited from a stoichiometric target using a KrF excimer laser (248 nm, 250 mJ/pulse, −2 J/cm2) as a function of substrate temperature, oxygen pressure and vacuum anneal conditions. The film composition and structure, as determined by RBS and XRD, were very sensitive to the deposition and subsequent anneal conditions. Stoichiometric films were deposited at low substrate temperatures (740 °C) but contained other orientations and phases. Predominantly c-axis oriented films were formed at high substrate temperatures (900 °C) and high background pressures of oxygen (200 mtorr). These films were semiconducting when quenched on oxygen or nitrogen following deposition. Slow cooling in a vacuum, yielded superconducting films with a maximum Tc-(onset) of 15 K and Tc(R=0) of 11 K. A variation of the deposition and anneal conditions indicated that loss of copper competed with the optimization of the carrier concentration.
In-situ observation of self-cleansing phenomena during ultra-high vacuum anneal of transition metal nitride thin films: Prospects for non-destructive photoelectron spectroscopy
