Investigation of CeO2 Buffer Layer Effects on the Voltage Response of YBCO Transition-Edge Bolometers

The effect on the thermal parameters of superconducting transition-edge bolometers produced on a single crystalline SrTiO3 (STO) substrate with and without a CeO2 buffer layer was investigated. Metal-organic deposition was used to deposit the 20-nm CeO2 buffer layer, whereas RF magnetron sputtering was applied to fabricate 150-nm-thick superconducting YBa2Cu3O7-delta (YBCO) thin film. The critical transition temperature for both of the YBCO films was 90 K, and the transition width was similar to 1.9 K. The bolometers fabricated from these samples were characterized with respect to the voltage phase and amplitude responses, and the results were compared with that of simulations conducted by applying a one-dimensional thermophysical model. It was observed that adding the buffer layer to the structure of the bolometer results in an increased response at higher modulation frequencies. Results from simulations made by fitting the thermal parameters in the model with and without an additional CeO2 layer were found to be in agreement with the experimental observations.