Reversible Control of In‐Plane Elastic Stress Tensor in Nanomembranes

Abstract

The physical properties of materials critically depend on the interatomic distances of the constituent atoms, which in turn can be tuned by introducing elastic strain (stress). While about four decades ago strain was generally regarded as a feature to be avoided in semiconductors, [1] strain engineering is nowadays ubiquitously used, e.g., to enhance the carrier mobility in transistors [2][3] and to achieve lasing action at reduced current densities in heterostructure lasers. [4] For this reason, its potential impact on our society has been compared to that of chemical alloying. [5] Strain can be used not only to enhance specific material/device properties, but also to impart completely new properties to a given material, thus opening the way to previously inaccessible applications. Examples are Ge turning into a direct-bandgap semiconductor suitable for lasers, [6][7][8][9] exciton dynamics tailoring in nanowires induced by strain gradients, [10] graphene electronic states engineering and strain-induced giant pseudomagnetic fields up to 300 T, [11][12] a topological insulator turning into a semiconductor, [13]

Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

“…Both schemes are more robust against small variations of the energy of the laser as well as fluctuations of the laser pump power. In addition, to really use these QDs in real-life applications, such as quantum repeater networks, the next step is to integrate them in photonic structures for boosting the flux of the XX and X photons and to gain control over the energy of the emitted photons using external perturbations 24 53 54 55 . We envisage that the implementation of these tasks in the GaAs QD system will soon lead to the fabrication of an ideal source of entangled photons.…”

Strain-inducedg-factor tuning in single InGaAs/GaAs quantum dots

“…As the strain-induced shift in the emission energy is at least a factor of 15 smaller than what has been reported in literature for similar devices [12,17], we expect that the observed effect can be greatly enhanced. Using novel devices an even larger tuning range will be possible [28][29][30]. By optimizing the size, shape, and composition of the dots, we can enhance the valence band contribution and improve even further.…”

Active tuning of the g -tensor in InGaAs/GaAs quantum dots via strain

“…By size-engineering of the QDs, the nominal value of the g-factor, can be brought close to zero, in absence of external strain. Addtionally, a much larger tuning range can be achieved by making use of more advanced devices [38][39][40], with reported strain values up to 1.5% [25]. In some of these devices, full anisotropic control over the in-plane strain tensor is possible.…”