A new broadband near-millimeter wave detector using mercury-cadmium-telluride

Abstract

By varying the mobility and cadmium mole fraction in samples of mercury-cadmium-telluride we have achieved a 50-fold increase in sensitivity over previous results. At 1.5 K and 105 GHz, the responsivity is approximately 50 V/W, corresponding to a Johnson-noise-limited NEP of 1.4 × 10⁻¹² ${W \mathord{\left/{\vphantom {W {\sqrt {Hz} }}} \right.\kern-\nulldelimiterspace} {\sqrt {Hz} }}$. In addition when used as a mixer, a 3 dB bandwidth of 25 MHz has been measured. The Kinch-Kogan theory of the temperature dependence of the responsivity appears to be in only qualitative agreement with the measured results.