Thin Pr–Ba–Cu–O Film Antenna-Coupled THz Bolometers for Room Temperature Operation

We report on the development of room temperature THz bolometers made from semiconducting PrBa₂Cu₃O_7-δ (PBCO) thin films on MgO substrate. PBCO thin films show a high temperature coefficient of resistance (TCR ≈ 1-2%/K) at low resistivity values (ρ ≈ 2000 μΩcm) in comparison to other semiconducting materials like amorphous silicon or vanadium oxide. A low resistivity enables efficient coupling to an integrated planar antenna required to couple THz radiation to micrometer sized detector elements. A detailed electrical characterization as well as radiation measurements at 0.65 THz of the 70-100 nm thick PBCO film microbridges embedded into log-spiral planar antennas have been performed. An electrical responsivity up to S=33 V/W and a noise equivalent power of NEP=1.52×10^-10 W/√Hz at a modulation frequency of 10 kHz limited by the measurement setup have been achieved.