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Modern opto-electronic devices are based on semiconductor heterostructures employing the process of electron-hole pair annihilation. In particular polar materials enable a variety of classic and even quantum light sources, whose on-going optimisation endeavours challenge generations of researchers. However, the key challenge - the inherent electric crystal polarisation of such materials - remains unsolved and deteriorates the electron-hole pair annihilation rate. Here, our approach introduces a sequence of reverse interfaces to compensate these polarisation effects, while the polar, natural crystal growth direction is maintained provoking a boost in device performance. Former research approaches like growth on less-polar crystal planes or even the stabilization of unnatural phases never reached industrial maturity. In contrast, our solution allows the adaptation of all established industrial processes, while the polarisation becomes adjustable; even across zero. Hence, our approach marks the onset of an entire class of ultra-fast and efficient devices based on any polar material.
Pyramidal quantum dots (QDs) grown in inverted recesses have demonstrated over the years an extraordinary uniformity, high spectral purity and strong design versatility. We discuss recent results, also in view of the Stranski-Krastanow competition an
We report the design and development of a piezoelectric sample rotation system, and its integration into an Oxford Instruments Kelvinox 100 dilution refrigerator, for orientation-dependent studies of quantum transport in semiconductor nanodevices at
We present experimental coherent two-dimensional Fourier transform spectra of the exciton resonances in semiconductor quantum wells for a pulse sequence that isolates two-quantum coherences. By measuring the real part of the spectra, we can determine
This paper presents an overview of scanning-gate microscopy applied to the imaging of electron transport through buried semiconductor nanostructures. After a brief description of the technique and of its possible artifacts, we give a summary of some
We investigate the dynamic nuclear polarization from the hyperfine interaction between nonequilibrium electronic spins and nuclear spins coupled to them in semiconductor nanostructures. We derive the time and position dependence of the induced nuclea