Project Details
Projekt Print View

SFB 787:  Semiconductor Nanophotonics: Materials, Models, Devices

Subject Area Physics
Computer Science, Systems and Electrical Engineering
Mathematics
Term from 2008 to 2019
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 43659573
 
Final Report Year 2020

Final Report Abstract

The Collaborative Research Center "Semiconductor Nanophotonics" (CRC 787) brought together three complementary research areas - Materials, Models, and Devices - aiming at the development of novel nanophotonic structures and devices. Based on the two most relevant families of semiconducting materials for optoelectronics (group III-arsenides and III-nitrides) significant advances in the growth and advanced characterization of semiconductor nanostructures have been made. This includes the realization of single site-controlled InGaAs quantum dots employing a novel buried stressor approach, paving the way for the demonstration of electrically operated and deterministic single photon sources with emission linewidth ≤ 25 µeV. Another highlight was the growth of stacked InAs submonolayer quantum dots and the determination of their atomic structure and optical properties. After integration of these stacked submonolayer quantum dots in optical amplifiers CRC 787 researchers were able to observe quantum-coherence effects at roomtemperature in ultrafast laser pulses. Furthermore, a new type of confined biexciton state was discovered in GaN quantum dots with spin configuration of s=+/-3, enabling new transition schemes for the biexcitonexciton decay, which is very promising for next generation quantum emitters. The CRC researchers were also able to reveal the atomic structure of non-polar group-III nitride semiconductor surfaces employing high resolution scanning tunneling microscopy techniques. The CRC has also made significant advances in theoretical and numerical modelling ranging from the description of fundamental optics, electronics, and vibronic properties of nanomaterials to the simulation of complex nanophotonic devices. This included a fundamental understanding of interactions like electron-lattice and light-matter interactions, electron-photon correlations, and Coulomb interaction on nanometer-scales which are essential for the next quantum revolution. For this purpose theoretical methods were developed to describe many particle dynamics, optical properties and spectroscopic results of semiconductor nanostructures. This enabled the device-scale simulation of electrically driven quantum light emitters such as single-photon sources based on semiconductor quantum dots by combining a hybrid quantum-classical model with cavity quantum electrodynamics. It also allowed the exploration of dephasing in solid-state quantum emitters via time-and temperature-dependent Hong-Ou-Mandel experiments. Furthermore, a theoretical framework to model the ultra-fast carrier dynamics in nano-structured gain media was developed in order to predict the complex light output dynamics ranging from short pulses to chaotic emission. Based on these fundamental breakthroughs and comprehensive understanding of the underlying physics a number of new nanophotonic devices have been realized with applications in quantum communication systems, data transfer, and I/O engines. The CRC researchers have realized ultra-high speed and energy efficient vertical cavity surface emitting lasers (VCSELs) and VCSEL arrays with record optical output power levels, modulation bandwidth, and digital data transmission rates. This includes the demonstration of the world’s most energy efficient VCSELs with with energy-to-data rates of 80 fJ/bit at bit rates of 40 Gb/s. These nanometer-scale lasers will be critical components for next generation information and communications technology (ICT) including Fifth Generation (5G) networks, and Internet of Things (IoT) systems. In addition, we were able to realize a silicon photonic I/O engine based on hybrid integration of VCSELs with silicon photonics for highly efficient chip-to-chip communication. We were also able to demonstrate electrically driven quantum key systems based on q-bit and entangled photon emitters operating at high q-bit rates and implement them in real information networks. Highlights include the development of in-situ e-beam lithography (EBL) and the deterministic integration of single InGaAs quantum dots into on-chip multimode interference beamsplitters using in-situ electron beam lithography as well as the realization of bright triggered twin-photon solid state sources. The demonstration of a stand-alone fiber-coupled single-photon source and the generation of on-demand frequency-locked indistinguishable photons as well as time-bin entangled photon pairs enabled CRC researchers to demonstrate a free-space optical link and the transmission of quantum information via single and entangled photons. CRC researchers were also able to push the wavelength limits of semiconductor emitters and demonstrate a new world record for the shortest wavelength AlGaN lasers emitting in the deep ultraviolet (UV) at 237 nm. Significant advances have also been made towards current-injection UV laser diodes with the first demonstration of MOVPE-grown AlGaN-based tunnel heterojunctions enabling fully transparent deep UV light emitting diodes. This breakthrough will be critical for UV laser diodes for applications in medical diagnostics, sensing, and 3D-printing. Finally, great strides have also been made in the development of high power and high brightness infrared (IR) laser diodes for applications in materials processing, optical clocks, and life sciences. This includes new concepts for high-power GaAs-based edge-emitting laser diodes with super large optical cavities (SLOC) that utilize photonic bandgap crystal (PBC) waveguides. Theselaser diodes exhibited extremely small divergence angles and an excellent beam quality.

Publications

 
 

Additional Information

Textvergrößerung und Kontrastanpassung