Low Noise Nanometer Scale Room-Temperature ${\hbox {YBa}}_{2}{\hbox {Cu}}_{3}{\hbox {O}}_{7-x}$ Bolometers for THz Direct Detection

We present a detailed investigation of the responsivity and the noise in room temperature THz direct detectors made of YBa₂Cu₃O_7-x (YBCO) thin-film nano-bolometers. The YBCO nano-bolometers are integrated with planar spiral antennas covering a frequency range from 100 GHz to 2 THz. The detectors were characterized at 1.6 THz, 0.7 THz, 400 GHz and 100 GHz. The maximum electrical responsivity of 70 V/W and a minimum noise equivalent power (NEP) of 50 pW/Hz^0.5 were measured, whereas the highest optical responsivity was 45 V/W. The (1/f) noise in nano-bolometers is independent on the device volume and can be found as (V_N/V)²=6×10^-11×1/f Hz^-1 for a given modulation frequency f and a dc voltage V.