The High-Performance Imaging Verification of Si:P Blocked Impurity Band Detector for Very-Long-Wave-Infrared Spectral Range

Abstract

Very-long-wave-infrared (VLWIR) photodetectors have attracted great attention from scientists worldwide in the ground and space-based detections, imaging and early warning. However, the application of VLWIR photodetectors on earth is limited by the difficulty of establishing a high spatial-resolution fine imaging system with high-performance detector and large size optical lens. In this work, the VLWIR Si-based blocked-impurity-band (BIB) detector is fabricated and its high-performance imaging system is constructed. The CVD growth progress is optimized by enhancing the doping concentration of absorption layer, and shortening the transition length between blocking and absorption layers. At the temperature of 4.2K, the blackbody responsivity of Si-based BIB detector reaches 20.78A/W and the Noise Equivalent Power is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.7\times 10^{-16}\text{W}$ </tex-math></inline-formula> /Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> at 2.6V. Based on the high performance Si-based BIB detector, an imaging verifying system is set up to detect different room-temperature objects. Its spatial and temperature resolution reaches <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$250~\mu \text{m}$ </tex-math></inline-formula> and 10mK, respectively. Our results indicate that with suitable optical imaging system, the BIB detector is more effective than the infrared detector of commercial thermal infrared imager in detecting room temperature or low temperature objects like metal. Our work is helpful for the further research on the large scale array integrated BIB imaging and detection system used on earth for explosives detection, biological nondestructive detection as well as security check.