The acoustic phonon limited mobility of two-dimensional electrons in an (001)AIGaAslGaAs heterojunction is calculated. It exceeds the highest experimentally achieved value of mobility by approximately six times at the liquid helium temperature.

No abstract

The non-stationary equation of diffusion in energy space is solved when the initial binding energy of the atom is much smaller than the thermal energy k,T (collisional scattering) or atomic energy (interaction with a microwave field). As the result, analytic expressions for the diffusive ionisation rate of Rydberg atoms are obtained in the regime of their non-stationary generation.

No abstract

Formation of bismuth nanocrystals in GaAsBi layers grown by molecular beam epitaxy at 330 °C substrate temperature and post-growth annealed at 750 °C is reported. Superlattices containing alternating 10 nm-thick GaAsBi and AlAs layers were grown on semi-insulating GaAs substrate. AlAs layers have served as diffusion barriers for Bi atoms, and the size of the nanoclusters which nucleated after sample annealing was correlating with the thickness of the bismide layers. Energy-dispersive spectroscopy and Raman scattering measurements have evidenced that the nanoparticles predominantly constituted from Bi atoms. Strong photoluminescence signal with photon wavelengths ranging from 1.3 to 1.7 μm was observed after annealing; its amplitude was scaling-up with the increased number of the GaAsBi layers. The observed photoluminescence band can be due to emission from Bi nanocrystals. The carried out theoretical estimates support the assumption. They show that due to the quantum size effect, the Bi nanoparticles experience a transition to the direct-bandgap semiconducting state.