High quality epitaxial YBa2Cu3O7−x(YBCO) thin films have been deposited on 12 &mgr;m thick (11¯02) oriented sapphire substrates using a CeO2buffer layer. Both layers were deposited by pulsed laser deposition (PLD) using a blackbody‐type heater. The YBCO films showed superconductive transition temperatures of 88–89.5 K and transition widths ≤0.5 K. Structural evaluation of the films indicate that the YBCO films arec‐axis oriented, with the YBCO (005) peak showing a rocking angle full width half‐maximum (FWHM) of about 0.7°. The &fgr;‐scans of the (103) YBCO peak indicate a high degree of in‐plane epitaxy with no signs of high angle grain boundaries. The high quality of these films combined with the low heat capacity of the substrates, make these structures ideal for infrared detector applications. ©1995 American Institute of Physics.