Quantum dot-based up-conversion photodetector,in which an infrared photodiode(PD)and a quantum dot light-emitting diode(QLED)are back-to-back connected,is a promising candidate for low-cost infrared imaging.However,th...Quantum dot-based up-conversion photodetector,in which an infrared photodiode(PD)and a quantum dot light-emitting diode(QLED)are back-to-back connected,is a promising candidate for low-cost infrared imaging.However,the huge efficiency losses caused by integrating the PD and QLED together hasn’t been studied sufficiently.This work revealed at least three origins for the efficiency losses.First,the PD unit and QLED unit usually didn’t work under optimal conditions at the same time.Second,the potential barriers and traps at the interconnection between PD and QLED units induced unfavorable carrier recombination.Third,much emitted visible light was lost due to the strong visible absorption in the PD unit.Based on the understandings on the loss mechanisms,the infrared up-conversion photodetectors were optimized and achieved a breakthrough photon-to-photon conversion efficiency of 6.9%.This study provided valuable guidance on how to optimize the way of integration for up-conversion photodetectors.展开更多
Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wav...Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wavelengths cannot be detected; in addition, their cost is high and their manufacturing process is complex. Therefore, it is meaningful and significant to extend absorption wavelength, to decrease cost, and to simplify the manufacturing process while maintaining high performance for photodetectors. Due to the properties of size-dependent bandgap tunability, low cost, facile processing,and substrate compatibility, solution–processed colloidal quantum dots(CQDs) have recently gained significant attention and become one of the most competitive and promising candidates for optoelectronic devices. Among these CQDs, lead chalcogenide CQDs are getting very prominent and are widely investigated. In this paper, the recent progress of infrared(IR) photodetectors based on lead sulfide(PbS), lead selenide(PbSe), and ternary PbS_x Se_(1-x) CQDs, and their underlying concepts, breakthroughs, and remaining challenges are reviewed, thus providing guidance for designing high-performance quantum-dot IR photodetectors.展开更多
Quantum dot infrared photodetectors are expected to be a competitive technology at high oper ation temperatures in the long and very long wavelength infrared spectral range.Despite the fact that they already achieved ...Quantum dot infrared photodetectors are expected to be a competitive technology at high oper ation temperatures in the long and very long wavelength infrared spectral range.Despite the fact that they already achieved notable success,the performance suffers from the thermionic emission of electrons from the quantum dots at elevated temperatures resulting in a decreasing responsivity.In order to provide an efficient carrier injection at high temperatures,quantum dot infrared photodetectors can be separated into two parts:an injection part and a detection part,so that each part can be separately optimized.In order to integrate such functionality into a device,a new class of quantum dot infrared photodetectors using quantum dot molecules will be introduced.In addition to a general discussion simulation results suggest a possibility to realize such a device.展开更多
During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview o...During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes(LEDs), QD infrared photodetectors(QDIPs) and QD intermediate band(QDIB) solar cells(SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.展开更多
本文报道了采用分子束外延技术制备的三色In As/Ga As量子点红外探测器.器件采用nin型结构,吸收区结构是在In Ga As量子阱中生长含有Al Ga As插入层的In As量子点,器件在77 K下的红外光电流谱有三个峰值:6.3,10.2和11μm.文中分析了它...本文报道了采用分子束外延技术制备的三色In As/Ga As量子点红外探测器.器件采用nin型结构,吸收区结构是在In Ga As量子阱中生长含有Al Ga As插入层的In As量子点,器件在77 K下的红外光电流谱有三个峰值:6.3,10.2和11μm.文中分析了它们的跃迁机制,并且分别进行了指认.因为有源区采用了不对称结构,所以器件在外加偏压正负方向不同时,光电流谱峰值的强度存在一些差异.不论在正偏压或者负偏压下,当偏压达到较高值,再进一步增大偏压时,都出现了对应于连续态的跃迁峰强度明显下降的现象,这是由量子点基态与阱外连续态的波函数交叠随着偏压进一步增大而迅速减小导致的.展开更多
基金supported by the following research fundings including:the National Natural Science Foundation of China(Nos.62005114,62204078 and U22A2072)Natural Science Foundation of Henan-Excellent Youth Scholar(No.232300421092)Open Fund of the State Key Laboratory of Integrated Optoelectronics+(IOSKL2020KF01).
文摘Quantum dot-based up-conversion photodetector,in which an infrared photodiode(PD)and a quantum dot light-emitting diode(QLED)are back-to-back connected,is a promising candidate for low-cost infrared imaging.However,the huge efficiency losses caused by integrating the PD and QLED together hasn’t been studied sufficiently.This work revealed at least three origins for the efficiency losses.First,the PD unit and QLED unit usually didn’t work under optimal conditions at the same time.Second,the potential barriers and traps at the interconnection between PD and QLED units induced unfavorable carrier recombination.Third,much emitted visible light was lost due to the strong visible absorption in the PD unit.Based on the understandings on the loss mechanisms,the infrared up-conversion photodetectors were optimized and achieved a breakthrough photon-to-photon conversion efficiency of 6.9%.This study provided valuable guidance on how to optimize the way of integration for up-conversion photodetectors.
基金Project supported by the Fund from the State Key Laboratory of Transducer Technology,China(Grant No.SKT1404)the Fund from the Key Laboratory of Photoelectronic Imaging Technology and System(Grant No.2017OEIOF02)at Beijing Institute of Technology,Ministry of Education of China
文摘Commercial photodetectors based on silicon are extensively applied in numerous fields. Except for their high performance, their maximum absorption wavelength is not over than 1100 nm and incident light with longer wavelengths cannot be detected; in addition, their cost is high and their manufacturing process is complex. Therefore, it is meaningful and significant to extend absorption wavelength, to decrease cost, and to simplify the manufacturing process while maintaining high performance for photodetectors. Due to the properties of size-dependent bandgap tunability, low cost, facile processing,and substrate compatibility, solution–processed colloidal quantum dots(CQDs) have recently gained significant attention and become one of the most competitive and promising candidates for optoelectronic devices. Among these CQDs, lead chalcogenide CQDs are getting very prominent and are widely investigated. In this paper, the recent progress of infrared(IR) photodetectors based on lead sulfide(PbS), lead selenide(PbSe), and ternary PbS_x Se_(1-x) CQDs, and their underlying concepts, breakthroughs, and remaining challenges are reviewed, thus providing guidance for designing high-performance quantum-dot IR photodetectors.
文摘Quantum dot infrared photodetectors are expected to be a competitive technology at high oper ation temperatures in the long and very long wavelength infrared spectral range.Despite the fact that they already achieved notable success,the performance suffers from the thermionic emission of electrons from the quantum dots at elevated temperatures resulting in a decreasing responsivity.In order to provide an efficient carrier injection at high temperatures,quantum dot infrared photodetectors can be separated into two parts:an injection part and a detection part,so that each part can be separately optimized.In order to integrate such functionality into a device,a new class of quantum dot infrared photodetectors using quantum dot molecules will be introduced.In addition to a general discussion simulation results suggest a possibility to realize such a device.
文摘During the last two decades, III-nitride-based quantum dots(QDs) have attracted great attentions for optoelectronic applications due to their unique electronic properties. In this paper, we first present an overview on the techniques of fabrication for III-nitride-based QDs. Then various optoelectronic devices such as QD lasers, QD light-emitting diodes(LEDs), QD infrared photodetectors(QDIPs) and QD intermediate band(QDIB) solar cells(SCs) are discussed. Finally, we focus on the future research directions and how the challenges can be overcome.
基金Supported by Launching Scientific Research Funds for Doctors(2012-B-04)National Natural Science Foundation of China(61307121,11274207)+1 种基金Industry Research Prroject of Datong City(2015018)Aeronautical Science Foundation of China(20122481002)
文摘本文报道了采用分子束外延技术制备的三色In As/Ga As量子点红外探测器.器件采用nin型结构,吸收区结构是在In Ga As量子阱中生长含有Al Ga As插入层的In As量子点,器件在77 K下的红外光电流谱有三个峰值:6.3,10.2和11μm.文中分析了它们的跃迁机制,并且分别进行了指认.因为有源区采用了不对称结构,所以器件在外加偏压正负方向不同时,光电流谱峰值的强度存在一些差异.不论在正偏压或者负偏压下,当偏压达到较高值,再进一步增大偏压时,都出现了对应于连续态的跃迁峰强度明显下降的现象,这是由量子点基态与阱外连续态的波函数交叠随着偏压进一步增大而迅速减小导致的.
