Highly c-axis oriented superconducting YBa2Cu3O7-x (YBCO) thin films with a zero-resistance temperature of 85.5 K and a critical current density of 1.9 x 10(3) 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-degrees-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.