Low Noise Nanometer Scale Room-Temperature <formula formulatype="inline"><tex Notation="TeX">${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7-x}$</tex> </formula> Bolometers for THz Direct Detection

Abstract

We present a detailed investigation of the responsivity and the noise in room temperature THz direct detectors made of ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7-x}$ (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 ${\hbox{50}} {\hbox{pW/Hz}}^{0.5}$ 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 $(V_{N}/V)^{2}=6\times 10^{-11}\times 1/f {\hbox{Hz}}^{-1}$ for a given modulation frequency $f$ and a dc voltage $V$ .