NO_2 sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However,traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here...NO_2 sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However,traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here, we report a simply and reliable flexible NO_2 sensor based on single-layer MoS_2. The flexible sensor exhibits high sensitivity to NO_2 gas due to ultra-large specific surface area and the nature of two-dimensional(2 D) semiconductor. When the NO_2 is 400 ppb(parts per billion), compared with the dark and strain-free conditions, the sensitivity of the single-layer sensor is enhanced to 671% with a625 nm red light-emitting diode(LED) illumination of 4 mW/cm^2 power under 0.67% tensile strain.More important, the response time is dramatically reduced to $16 s and it only needs $65 s to complete90% recovery. A theoretical model is proposed to discuss the microscopic mechanisms. We find that the remarkable sensing characteristics are the result of coupling among piezoelectricity, photoelectricity and adsorption-desorption induced charges transfer in the single-layer MoS_2 Schottky junction based device.Our work opens up the way to further enhancements in the sensitivity of gas sensor based on single-layer MoS_2 by introducing photogating and piezo-phototronic effects in mesoscopic systems.展开更多
基金supported by the National Key Research and Development Program of China(2016YFA0202703,2016YFA0202704)the National Natural Science Foundation of China(51472056)+1 种基金the Thousands Talents Plan For Pioneer Researcher And His Innovation Team,Chinathe Recruitment Program of Global Youth Experts,China
文摘NO_2 sensors with ultrahigh sensitivity are demanded for future electronic sensing systems. However,traditional sensors are considerably limited by the relative low sensitivity, high cost and complicated process. Here, we report a simply and reliable flexible NO_2 sensor based on single-layer MoS_2. The flexible sensor exhibits high sensitivity to NO_2 gas due to ultra-large specific surface area and the nature of two-dimensional(2 D) semiconductor. When the NO_2 is 400 ppb(parts per billion), compared with the dark and strain-free conditions, the sensitivity of the single-layer sensor is enhanced to 671% with a625 nm red light-emitting diode(LED) illumination of 4 mW/cm^2 power under 0.67% tensile strain.More important, the response time is dramatically reduced to $16 s and it only needs $65 s to complete90% recovery. A theoretical model is proposed to discuss the microscopic mechanisms. We find that the remarkable sensing characteristics are the result of coupling among piezoelectricity, photoelectricity and adsorption-desorption induced charges transfer in the single-layer MoS_2 Schottky junction based device.Our work opens up the way to further enhancements in the sensitivity of gas sensor based on single-layer MoS_2 by introducing photogating and piezo-phototronic effects in mesoscopic systems.
