Ti Hot Electron Bolometers with Johnson Noise Readout for Terahertz Radiation Detection

A hot electron bolometer (HEB) with Johnson noise readout is an attractive technique for radiation detection due to its high sensitivity, wide operating temperature range, and large dynamic range. In this paper, we present the development of a terahertz HEB based on Johnson noise readout. The HEB consists of a titanium microbridge connected to two high-energy-gap niobium contacts for confining hot electrons. We measured the thermal conductance and noise equivalent power (NEP) of the HEB at different bath temperatures. We find that the thermal conductance due to the electron–phonon interaction increases with temperature as T2.5. At 3.0 K, the thermal conductance is found to be 37.9 ± 1.4 nW/K and the electrical NEP is as low as 23.0 ± 0.8 pW/Hz\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \sqrt {\text{Hz}} $$\end{document}. In addition, we find that the HEB works efficiently up to 15 μW input power.