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The interaction of Mn with Ge quantum dots (QD), which are bounded by {105} facets, and the strained Ge wetting layer (WL), terminated by a (001) surface, is investigated with scanning tunneling microscopy (STM). Mn is deposited on the Ge…
Formation of MnAs quantum dots in a regular ring-like distribution has been found on MBE-grown (GaMn)As surfaces after low-temperature annealing under As capping. The Mn was supplied by out-diffusing Mn interstitials from (GaMn)As. With 5…
Realizing single photon sources emitting in the telecom band on silicon substrates is essential to reach complementary-metal-oxide-semiconductor (CMOS) compatible devices that secure communications over long distances. In this work, we…
The formation of dislocation-free three-dimensional islands during the heteroepitaxial growth of lattice-mismatched materials has been observed experimentally for several material systems. The equilibrium shape of the islands is governed by…
We demonstrate nearly-spherical, strain-free, self-assembled Ge quantum dots (QDs) fully encapsulated by AlAs, grown on (100) GaAs by molecular beam epitaxy (MBE). The QDs were formed without a wetting layer using a high temperature,…
We used AlGaSb/AlGaAs material system for a theoretical study of photovoltaic performance of the proposed GaAs-based solar cell in which the type-II quantum dot (QDs) absorber is spatially separated from the depletion region. Due to…
A direct observation of nucleation of Ge hut clusters formed by ultrahigh vacuum molecular beam epitaxy is reported for the first time. The nuclei of the pyramidal and wedge-like clusters have been observed on the wetting layer blocks and…
We demonstrate the Au-assisted growth of semiconductor nanowires on different engineered substrates. Two relevant cases are investigated: GaAs/AlGaAs heterostructures capped by a $50 {\rm nm}$-thick InAs layer grown by molecular beam…
By a cleaved-edge overgrowth method with molecular beam epitaxy and a (110) growth-interrupt-anneal, we have fabricated a GaAs quantum well exactly 30 monolayers thick bounded by atomically smooth AlGaAs hetero-interfaces without atomic…
Hybrid superconductor-semiconductor heterostructures are a promising platform for quantum devices based on mesoscopic and topological superconductivity. In these structures, a semiconductor must be in close proximity to a superconductor and…
We studied and optimized the molecular beam epitaxy of GaSb layers on vicinal (001) Si substrates using a GaAs nucleation layer. An in-depth analysis of the different growth stages under optimized conditions revealed the formation of a high…
Self-assembled, epitaxially-grown InAs/GaAs quantum dots are promising semiconductor quantum emitters that can be integrated on a chip for a variety of photonic quantum information science applications. However, self-assembled growth…
Epitaxial GaAs quantum dots grown by droplet etching have recently shown excellent properties as sources of single photons as well as entangled photon pairs. Integration in some nanophotonic structures requires surface-to-dot distances of…
We report on the systematic investigation of the optical properties of a selectively grown quantum dot gain material assisted by block-copolymer lithography for potential applications in active optical devices operating in the wavelength…
We evidence the influence of surface effects for InAs quantum dots embedded into GaAs photonic nanowires used as efficient single photon sources. We observe a continuous temporal drift of the emission energy that is an obstacle to resonant…
GaAs-based nanowires hosting active quantum heterostructures provide a promising route toward monolithic integration of single-photon sources on silicon, a key requirement for scalable quantum photonics. However, ultrathin axial…
Recent experimental measurements, without any theoretical guidance, showed that isotropic polarization response can be achieved by increasing the number of QD layers in a QD stack. Here we analyse the polarization response of multi-layer…
We analyse the optical properties of InAs$_{1-x}$Sb$_{x}$/Al$_{y}$In$_{1-y}$As quantum wells (QWs) grown by molecular beam epitaxy on relaxed Al$_{y}$In$_{1-y}$As metamorphic buffer layers (MBLs) using GaAs substrates. The use of…
We present molecular beam epitaxial grown single- and double-side $\delta$-doped InAlSb/InSb quantum wells with varying distances down to 50 nm to the surface on GaSb metamorphic buffers. We analyze the surface morphology as well as the…
By combining band gap engineering with the self-organized growth of quantum dots, we present a scheme of adjusting the mid-infrared absorption properties to desired energy transitions in quantum dot based photodetectors. Embedding the self…