Bolometric sensor with high tcr and tunable low resistivity

Abstract

The present invention provides a novel way of operating sensing elements or bolometers in the resistive hysteresis region of a phase-transitioning VO(or doped VO) films. The invention is based on a novel principle that minor hysteresis loops inside the major loop become single-valued or non-hysteretic for sufficiently small temperature excursions. This single valued R(T) branches being characterized by essentially the same temperature coefficient of resistivity (TCR) as the semiconducting phase at room temperature. These non-hysteretic branches (NHB) can be located close to the metallic-phase end of the major loop, thus providing for tunable resistivity orders of magnitude lower than that of a pure semiconducting phase. Operating the Focal Plan Array in one of these NHBs allows for having high TCR and low resistivity simultaneously. Means for measuring of the sensor R(T) characteristic is provided together with the means of achieving and controlling the correct sensor positioning at the operating temperature inside one of these NHBs.