We study a superlattice of silicene and hexagonal boron nitride by first principles calculations and demonstrate that the interaction between the layers of the superlattice is very small. As a consequence, quasi free-standing silicene is realized in this superlattice. In particular, the Dirac cone of silicene is preserved. Due to the wide band gap of hexagonal boron nitride, the superlattice re...

Recent studies have predicted that heterostructure superlattices can enhance the effective thermoelectric power factor significantly through selective emission of hot carriers via thermionic emission. Here, we study the potential of SiGe/Si superlattices for power generation at high temperatures. A detailed theory based on Boltzmann transport equation is developed which takes into account multi...

Driven primarily by scientific curiosity, but also by the potential applications of intense sources of coherent sound, researchers have targeted the phonon laser (saser) since the invention of the optical laser over 50 years ago. Here we fabricate a vertical cavity structure designed to operate as a saser oscillator device at a frequency of 325 GHz. It is based on a semiconductor superlattice g...

We report on a possibility of efficient engineering of the acoustic phonon energy spectrum in multishell tubular structures produced by a novel high-tech method of self-organization of microand nano-architectures. The strain-driven roll-up procedure paved the way for novel classes of metamaterials such as single semiconductor radial microand nano-crystals and multi-layer spiral microand nano-su...

Related Articles GaN/AlGaN waveguide quantum cascade photodetectors at λ ≈ 1.55μm with enhanced responsivity and 40GHz frequency bandwidth Appl. Phys. Lett. 102, 011135 (2013) Optimization of thickness and doping of heterojunction unipolar barrier layer for dark current suppression in long wavelength strain layer superlattice infrared detectors Appl. Phys. Lett. 102, 013509 (2013) Metal-semicon...

We report the study of lasing modes in broad-area, equilateral-triangular laser cavities. An alternative approach is proposed to study optical modes in equilateral triangular cavities in an analytical form. The modes were obtained by examining the simplest optical paths inside the cavity, which yields the final solution with the boundary conditions. The cavities can be fabricated from semicondu...

Although coherent twin boundaries require little energy to form in nanoscale single crystals, their influence on properties can be dramatic. In recent years, some important steps forward have been made in understanding and controlling twinning processes at the nanoscale, making possible the fabrication of nanoengineered twinning superlattices in crystalline nanowires. These advances have opened...

We present a high-speed asynchronous optical sampling system, based on two different Kerr-lens mode-locked lasers with a GHz repetition rate: An Yb:KYW oscillator and a Ti:sapphire oscillator are synchronized in a master-slave configuration at a repetition rate offset of a few kHz. This system enables two-colour pump-probe measurements with resulting noise floors below 10⁻⁶ at a data aquisition...

We study terahertz radiation induced ratchet currents in low dimensional semiconductor structures with a superimposed one-dimensional lateral periodic potential. The periodic potential is produced by etching a grating into the sample surface or depositing metal stripes periodically on the sample top. Microscopically, the photocurrent generation is based on the combined action of the lateral per...