Due to thermal carriers generated by a narrow mid-infrared energy gap,cooling is always necessary to achieve ideal photodetection.In quantum dot(QD),the electron thermal generation should be reduced with quantum confi...Due to thermal carriers generated by a narrow mid-infrared energy gap,cooling is always necessary to achieve ideal photodetection.In quantum dot(QD),the electron thermal generation should be reduced with quantum confinement in all three dimensions.As a result,there would be a great potential to realize high-operating-temperature(HOT)QD mid-IR photodetectors,though not yet achieved.Taking the advantages of colloidal nanocrystals’solution processability and precise doping control by surface dipoles,this work demonstrates a HOT mid-infrared photodetector with a QD gradient homojunction.The detector achieves background-limited performance with D^(*)=2.7×1011 Jones on 4.2μm at 80 K,above 10^(11) Jones until 200 K,above 10^(10 )Jones until 280 K,and 7.6×10^(9) Jones on 3.5μm at 300 K.The external quantum efficiency also achieves more than 77%with responsivity 2.7 A/W at zero bias.The applications such as spectrometers,chemical sensors,and thermal cameras,are also approved,which motivate interest in low-cost,solution-processed and high-performance mid-infrared photodetection beyond epitaxial growth bulk photodetectors.展开更多
Image data acquired with fused multispectral information can be used for effective identification and navigation owing to additional information beyond human vision,including thermal distribution,night vision,and mole...Image data acquired with fused multispectral information can be used for effective identification and navigation owing to additional information beyond human vision,including thermal distribution,night vision,and molecular composition.However,the construction of photodetectors with such capabilities is hindered by the structural complexity arising from the integration of multiple semiconductor junctions with distinct energy gaps and lattice constants.In this work,we develop a colloidal quantum-dot dual-mode detector capable of detecting,separating,and fusing photons from various wavelength ranges.Using three vertically stacked colloidal quantum-dot homojunctions with alternating polarity,single-band short-wave infrared imaging and fused-band imaging(short-wave and mid-wave infrared)can be achieved with the same detector by controlling bias polarity and magnitude.The dual-mode detectors show detectivity up to 8×10^(10)Jones at the fused-band mode and 3.1×10^(11)Jones at the single-band mode,respectively.Without image post-processing algorithms,the dual-mode detectors could provide both night vision and thermal information-enhanced night vision imaging capability.To the best of our knowledge,this is the first colloidal quantum-dot detector that can achieve such functionality.The operation mode can be changed at a high frequency up to 1.7 MHz,making it possible to achieve simultaneously dual-mode imaging and remote temperature sensing.展开更多
基金National Natural Science Foundation of China(No.62105022)M.C.is also sponsored by Beijing Nova Program(No.Z211100002121069)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.YESS20210142)National Key R&D Program of China(2021YFA0717600).
文摘Due to thermal carriers generated by a narrow mid-infrared energy gap,cooling is always necessary to achieve ideal photodetection.In quantum dot(QD),the electron thermal generation should be reduced with quantum confinement in all three dimensions.As a result,there would be a great potential to realize high-operating-temperature(HOT)QD mid-IR photodetectors,though not yet achieved.Taking the advantages of colloidal nanocrystals’solution processability and precise doping control by surface dipoles,this work demonstrates a HOT mid-infrared photodetector with a QD gradient homojunction.The detector achieves background-limited performance with D^(*)=2.7×1011 Jones on 4.2μm at 80 K,above 10^(11) Jones until 200 K,above 10^(10 )Jones until 280 K,and 7.6×10^(9) Jones on 3.5μm at 300 K.The external quantum efficiency also achieves more than 77%with responsivity 2.7 A/W at zero bias.The applications such as spectrometers,chemical sensors,and thermal cameras,are also approved,which motivate interest in low-cost,solution-processed and high-performance mid-infrared photodetection beyond epitaxial growth bulk photodetectors.
基金National Key Research and Development Program of China(2021YFA0717600)National Natural Science Foundation of China(62035004,62105022)。
文摘Image data acquired with fused multispectral information can be used for effective identification and navigation owing to additional information beyond human vision,including thermal distribution,night vision,and molecular composition.However,the construction of photodetectors with such capabilities is hindered by the structural complexity arising from the integration of multiple semiconductor junctions with distinct energy gaps and lattice constants.In this work,we develop a colloidal quantum-dot dual-mode detector capable of detecting,separating,and fusing photons from various wavelength ranges.Using three vertically stacked colloidal quantum-dot homojunctions with alternating polarity,single-band short-wave infrared imaging and fused-band imaging(short-wave and mid-wave infrared)can be achieved with the same detector by controlling bias polarity and magnitude.The dual-mode detectors show detectivity up to 8×10^(10)Jones at the fused-band mode and 3.1×10^(11)Jones at the single-band mode,respectively.Without image post-processing algorithms,the dual-mode detectors could provide both night vision and thermal information-enhanced night vision imaging capability.To the best of our knowledge,this is the first colloidal quantum-dot detector that can achieve such functionality.The operation mode can be changed at a high frequency up to 1.7 MHz,making it possible to achieve simultaneously dual-mode imaging and remote temperature sensing.
