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Atomic hydrogen etching on the pulsed laser deposited (PLD) diamond-like carbon (DLC) films were examined in situ by using Raman spectroscopy. Thermal annealing of the as-prepared DLC films was found to alter the D-band (∼1355 cm −1 ) and G-band (∼1582 cm −1 ) from unresolved features at room temperature to clearly separated bands at above 500°C, indicating graphitization of the films. The presence of atomic hydrogen retards graphitization at temperatures lower than 500°C, presumably because reactive atomic hydrogen formed sp 3 -bonding carbons which prevented graphitization at below 500°C, while at above 500°C, the hydrogen etches away disordered structure of the DLC film as the intensity changes of the D-bands demonstrate.

YBa2Cu3O7−δ (YBCO) thin films were deposited on n-type (100) silicon wafers with yttria-stabilized zirconia (YSZ) buffer layers by a laser ablation technique. The YSZ layer had a thickness of about 60 nm, and was oriented preferentially in the (100) direction. The YBCO films were found to be preferentially (001) oriented, and had a superconducting critical temperature (Tc) above 85 K. Pure gold ohmic contacts were made on both sides of the YBCO/YSZ/Si structure and its I-V characteristics revealed a diode behavior. The turn-on and breakdown voltages are 1.3 and 20.34 V, respectively, at temperatures below the Tc. The ideality factor η had values of 13, 9.5 and 7 at room temperature, 100 and 50 K, respectively. Better superconductivity, lower operation temperature, and thinner buffer layers would result in better rectification.