Fast thermoelectric response of normal state YBa2Cu3O7−δ films

Normal state YBa2Cu3O7−δ films, epitaxially grown ‘‘off‐c axis’’ with tilt angles up to 20° are shown to be fast thermoelectric detectors for radiation from UV to far infrared wavelengths. Upon radiation heating of the tilted films a thermoelectric voltage arises due to the anisotropy of the thermopower in YBa2Cu3O7−δ. The response time is limited by the decaying temperature gradient and thus by heat diffusion. For thin films we have measured a response time from ≲1 ns in the UV to ∼5 ns in the far infrared. Because of the wavelength dependent reflectivity, the responsivity of the films varies between 0.5 V/MW and 20 V/MW. Thus, thin tilted YBa2Cu3O7−δ films can be used as fast room temperature detectors over a wide spectral range.