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1 Introduction
More quantum dots for photonic quantum technologies were brought up by
P. Michler from the University of Stuttgart, whose group at the Center for Integrated
Quantum Science and Technology (IQST) and SCoPE demonstrated super-resolving
phase measurements based on two-photon N00N states, which were generated by
quantum-dot single-photon sources. Moreover, he reported first efforts to perform
on-chip quantum sensing. In his group’s work, the bosonic nature of light was utilised
through the Hong–Ou–Mandel effect on a beam splitter.
In addition to conventional concepts incorporating epitaxially grown quantum
dots, the work presented by W. Fang from the State Key Laboratory of Modern Optical
Instrumentation and ZJU demonstrated high-purity, electrically-driven, and roomtemperature single-photon sources based on colloidal quantum dots. Such CdSe/CdS
core/shell quantum dots in solution-processed devices were reported to yield highpurity single photons with a low working voltage.
These quantum technologies of the second generation were preceded by quantum
technologies of the first generation, such as LEDs and lasers. Indeed, semiconductor
light source technologies have remained very attractive due to their maturity and
good integrability in existing technologies.
Based on photonic engineering, G. Xu and his co-workers from the Key Laboratory of Infrared Imaging Materials and Detectors in Shanghai demonstrated a novel
cavity concept for THz quantum-cascade lasers, which can operate at elevated (cryogenic) temperatures and exhibit highly efficient power extraction owing to the use
of a grating coupler.
While lasers and single-photon sources are highly demanded for current and
next-generation applications, LEDs have not lost their appeal as fundamental platform for illumination and light-based technologies. For instance, LEDs based on
high-performance solution-processed quantum dots, short QLEDs, have promised
application in display technologies. Y. Jin from the State Key Laboratory of Silicon
Materials and ZJU reviewed activities associated with QLEDs including material
chemistry of charge-transporting layers, mechanism studies and the optimisation of
prototype devices.
On the optoelectronic device side, high performance graphene/silicon photodetectors and image sensors were reported by Y. Xu, ZJU, making use of the integration
of 2D materials into CMOS device design and fabrication. Numerous examples operating in the UV, near-IR or mid-IR spectral range were highlighted in this context,
with the aim to solve the typical problems of silicon-based photodetectors and image
sensors.
Similarly, H. Zhu from the Hangzhou Dianzi University and his co-workers
focused on improved photodetectors by developing blocked-impurity-band (BIB)
THz photodetectors using a periodic metal structure adopted in the design of the
BIB device. The demonstration of a superior performance in a new operation mode
suggested the development of lower-cost and potentially mass-producible THz detectors.
More exotic optoelectronics were represented by oxide-based neuromorphic transistors for neuromorphic computation, highlighted by Q. Wan from the Nanjing University. Accordingly, artificial synapses and neurons were proposed based on proton-
1 Introduction
More quantum dots for photonic quantum technologies were brought up by
P. Michler from the University of Stuttgart, whose group at the Center for Integrated
Quantum Science and Technology (IQST) and SCoPE demonstrated super-resolving
phase measurements based on two-photon N00N states, which were generated by
quantum-dot single-photon sources. Moreover, he reported first efforts to perform
on-chip quantum sensing. In his group’s work, the bosonic nature of light was utilised
through the Hong–Ou–Mandel effect on a beam splitter.
In addition to conventional concepts incorporating epitaxially grown quantum
dots, the work presented by W. Fang from the State Key Laboratory of Modern Optical
Instrumentation and ZJU demonstrated high-purity, electrically-driven, and roomtemperature single-photon sources based on colloidal quantum dots. Such CdSe/CdS
core/shell quantum dots in solution-processed devices were reported to yield highpurity single photons with a low working voltage.
These quantum technologies of the second generation were preceded by quantum
technologies of the first generation, such as LEDs and lasers. Indeed, semiconductor
light source technologies have remained very attractive due to their maturity and
good integrability in existing technologies.
Based on photonic engineering, G. Xu and his co-workers from the Key Laboratory of Infrared Imaging Materials and Detectors in Shanghai demonstrated a novel
cavity concept for THz quantum-cascade lasers, which can operate at elevated (cryogenic) temperatures and exhibit highly efficient power extraction owing to the use
of a grating coupler.
While lasers and single-photon sources are highly demanded for current and
next-generation applications, LEDs have not lost their appeal as fundamental platform for illumination and light-based technologies. For instance, LEDs based on
high-performance solution-processed quantum dots, short QLEDs, have promised
application in display technologies. Y. Jin from the State Key Laboratory of Silicon
Materials and ZJU reviewed activities associated with QLEDs including material
chemistry of charge-transporting layers, mechanism studies and the optimisation of
prototype devices.
On the optoelectronic device side, high performance graphene/silicon photodetectors and image sensors were reported by Y. Xu, ZJU, making use of the integration
of 2D materials into CMOS device design and fabrication. Numerous examples operating in the UV, near-IR or mid-IR spectral range were highlighted in this context,
with the aim to solve the typical problems of silicon-based photodetectors and image
sensors.
Similarly, H. Zhu from the Hangzhou Dianzi University and his co-workers
focused on improved photodetectors by developing blocked-impurity-band (BIB)
THz photodetectors using a periodic metal structure adopted in the design of the
BIB device. The demonstration of a superior performance in a new operation mode
suggested the development of lower-cost and potentially mass-producible THz detectors.
More exotic optoelectronics were represented by oxide-based neuromorphic transistors for neuromorphic computation, highlighted by Q. Wan from the Nanjing University. Accordingly, artificial synapses and neurons were proposed based on proton-