F. Schäffler
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View article: Single SiGe quantum dot emission deterministically enhanced in a high-Q photonic crystal resonator
Single SiGe quantum dot emission deterministically enhanced in a high-Q photonic crystal resonator Open
We report the resonantly enhanced radiative emission from a single SiGe quantum dot (QD), which is deterministically embedded into a bichromatic photonic crystal resonator (PhCR) at the position of its largest modal electric field by a sca…
View article: Single SiGe Quantum Dot Emission Deterministically Enhanced in a High-Q Photonic Crystal Resonator
Single SiGe Quantum Dot Emission Deterministically Enhanced in a High-Q Photonic Crystal Resonator Open
We report the resonantly enhanced radiative emission from a single SiGe quantum dot (QD), which is deterministically embedded into a bichromatic photonic crystal resonator (PhCR) at the position of its largest modal electric field by a sca…
View article: Advanced hydrogenation process applied on Ge on Si quantum dots for enhanced light emission
Advanced hydrogenation process applied on Ge on Si quantum dots for enhanced light emission Open
For the development of photonic integrated circuits, it is mandatory to implement light sources on a Si-on-insulator (SOI) platform. However, point defects in the Si matrix and, e.g., at the Si/SiO2 interface act as nonradiative recombinat…
View article: In-Situ Annealing and Hydrogen Irradiation of Defect-Enhanced Germanium Quantum Dot Light Sources on Silicon
In-Situ Annealing and Hydrogen Irradiation of Defect-Enhanced Germanium Quantum Dot Light Sources on Silicon Open
While light-emitting nanostructures composed of group-IV materials fulfil the mandatory compatibility with CMOS-fabrication methods, factors such as the structural stability of the nanostructures upon thermal annealing, and the ensuing pho…
View article: Quantum Dots: Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots (Ann. Phys. 6/2019)
Quantum Dots: Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots (Ann. Phys. 6/2019) Open
Different recombination paths can strongly influence the optical properties of quantum dots. The green, red, and blue surfaces indicate the probability densities of heavy-hole, Δz, and Δxy electron wave-functions, respectively, as discusse…
View article: Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots
Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots Open
In this work, it is shown how different carrier recombination paths significantly broaden the photoluminescence (PL) emission bandwidth observed in type‐II self‐assembled SiGe/Si(001) quantum dots (QDs). QDs grown by molecular beam epitaxy…
View article: Single-Shot Readout of Hole Spins in Ge
Single-Shot Readout of Hole Spins in Ge Open
The strong atomistic spin-orbit coupling of holes makes single-shot spin readout measurements difficult because it reduces the spin lifetimes. By integrating the charge sensor into a high bandwidth radio frequency reflectometry setup, we w…
View article: Hole spin resonance in Ge double quantum dots
Hole spin resonance in Ge double quantum dots Open
Spins in isotopically purified Si have shown record coherence times and fidelities making them promising candidates for scalable quantum circuits. One of the key ingredients for realizing such circuits will be a strong coupling of spins to…
View article: Room-Temperature Group-IV LED Based on Defect-Enhanced Ge Quantum Dots
Room-Temperature Group-IV LED Based on Defect-Enhanced Ge Quantum Dots Open
As recently demonstrated, defect-enhanced Ge quantum dots (Ge-DEQDs) in a crystalline Si matrix can be employed as CMOS-compatible gain material in optically pumped lasers. Due to the stability of their optical properties up to temperature…
View article: Realization of high-<i>Q</i>/<i>V</i> photonic crystal cavities defined by an effective Aubry-André-Harper bichromatic potential
Realization of high-<i>Q</i>/<i>V</i> photonic crystal cavities defined by an effective Aubry-André-Harper bichromatic potential Open
We report on the realization of high-Q/V photonic crystal cavities in thin silicon membranes, with resonances around 1.55 μm wavelength. The cavity designs are based on a recently proposed photonic crystal implementation of the Aubry-André…
View article: Enhanced Telecom Emission from Single Group-IV Quantum Dots by Precise CMOS-Compatible Positioning in Photonic Crystal Cavities
Enhanced Telecom Emission from Single Group-IV Quantum Dots by Precise CMOS-Compatible Positioning in Photonic Crystal Cavities Open
Efficient coupling to integrated high-quality-factor cavities is crucial for the employment of germanium quantum dot (QD) emitters in future monolithic silicon-based optoelectronic platforms. We report on strongly enhanced emission from si…
View article: Photoluminescence enhancement through vertical stacking of defect-engineered Ge on Si quantum dots
Photoluminescence enhancement through vertical stacking of defect-engineered Ge on Si quantum dots Open
In this work, we show that the room-temperature photoluminescence intensity from Ge ion-bombarded (GIB) epitaxial Ge on Si quantum dots (QD) can be improved by their vertical stacking. We stress that the growth of GIB-QD multilayers is mor…
View article: Free-running Sn precipitates : An efficient phase separation mechanism for metastable Ge$_{1-x}$Sn$_{x}$ epilayers
Free-running Sn precipitates : An efficient phase separation mechanism for metastable Ge$_{1-x}$Sn$_{x}$ epilayers Open
We report on the temperature stability of pseudomorphic GeSn films grown by molecular beam epitaxy on Ge(001) substrates. Both the growth temperature-dependence and the influence of post-growth annealing steps were investigated. In either …
View article: Laser Level Scheme of Self-Interstitials in Epitaxial Ge Dots Encapsulated in Si
Laser Level Scheme of Self-Interstitials in Epitaxial Ge Dots Encapsulated in Si Open
Recently, it was shown that lasing from epitaxial Ge quantum dots (QDs) on Si substrates can be obtained if they are partially amorphized by Ge ion bombardment (GIB). Here, we present a model for the microscopic origin of the radiative tra…
View article: Local Density-of-States Mapping in Photonic Crystal Resonators by Deterministically Positioned Germanium Quantum Dots
Local Density-of-States Mapping in Photonic Crystal Resonators by Deterministically Positioned Germanium Quantum Dots Open
We report on mapping of the local density of states in L3 photonic crystal resonators (PCR) via deterministically positioned single Ge quantum dots (QDs). Perfect site-control of Ge QDs on pre-patterned silicon-on-insulator substrates was …
View article: Lasing from Glassy Ge Quantum Dots in Crystalline Si
Lasing from Glassy Ge Quantum Dots in Crystalline Si Open
Semiconductor light-emitters compatible with standard Si integration technology (SIT) are of particular interest for overcoming limitations in the operating speed of microelectronic devices. Light sources based on group IV elements would b…
View article: Nanoimprinted superlattice metallic photonic crystal as ultraselective solar absorber
Nanoimprinted superlattice metallic photonic crystal as ultraselective solar absorber Open
Here, a two-dimensional superlattice metallic photonic crystal (PhC) and its fabrication by nanoimprint lithography on tantalum substrates are presented. The superior tailoring capacity of the superlattice PhC geometry is used to achieve s…
View article: Optical properties of individual site-controlled Ge quantum dots
Optical properties of individual site-controlled Ge quantum dots Open
We report photoluminescence (PL) experiments on individual SiGe quantum dots (QDs) that were epitaxially grown in a site-controlled fashion on pre-patterned Si(001) substrates. We demonstrate that the PL line-widths of single QDs decrease …
View article: Efficient room-temperature light-emitters based on partly amorphised Ge quantum dots in crystalline Si
Efficient room-temperature light-emitters based on partly amorphised Ge quantum dots in crystalline Si Open
Semiconductor light emitters compatible with standard Si integration technology (SIT) are of particular interest for overcoming limitations in the operating speed of microelectronic devices 1-3. Light sources based on group-IV elements wou…
View article: Photoluminescence investigation of strictly ordered Ge dots grown on pit-patterned Si substrates
Photoluminescence investigation of strictly ordered Ge dots grown on pit-patterned Si substrates Open
We investigate the optical properties of ordered Ge quantum dots (QDs) by means of micro-photoluminescence spectroscopy (PL). These were grown on pit-patterned Si(001) substrates with a wide range of pit-periods and thus inter QD-distances…