In situ laser deposition of superconducting YBa₂Cu ₃O_7-x thin films on GaAs substrates

Highly c-axis oriented superconducting YBa₂Cu₃O _7-x (YBCO) thin films with a zero-resistance temperature of 85.5 K and a critical current density of 1.9×10³ A/cm² at 77 K and zero field, respectively, have been deposited on GaAs substrates by in situ laser ablation. A barrier layer using a combination of yttrium-stabilized ZrO₂ (YSZ) and Si₃N₄ proved to be a most successful buffer on GaAs when YBCO was deposited at relatively high temperature, around 650°C. The electrical properties of the YBCO films were very dependent on YSZ deposition conditions. The electrical and structural relationship between YBCO films and the YSZ deposition conditions is further investigated by cross-section scanning electron microscopy and Auger electron spectroscopy depth profiling.