Investigation Of The Shape Of A Cloud Of Electron-hole Droplets In Germanium

Absorption and scattering of light are used to investigate a cloud of electron-hole drops in Ge at 2°K. We find a drop size of 2 m, from light scattering; and use an Abel transform to unfold the absorption data and obtain a complete droplet density map. The cloud is distinctly nonspherical. The droplet penetration in a direction perpendicular to the surface of excitation is 1.5 times greater than that in a parallel direction. This result is discussed in terms of alternative models for cloud formation. © 1976 The American Physical Society.13125603560

Magnetic field dependence of the exciton energy in a quantum disk

The groundstate energy and binding energy of an exciton, confined in a^M quantum disk, are calculated as a function of an external magnetic field. The confinement potential is a hard wall of finite height. The diamagnetic shift is investigated for magnetic fields up to 40$T$. Our results are applied to $In_{y}Al_{1-y}As/Al_{x}Ga_{1-x}As$ self-assembled quantum dots and very good agreement with experiments is obtained. Furthermore, we investigated the influence of the dot size on the diamagnetic shift by changing the disk radius. The exciton excited states are found as a function of the magnetic field. The relative angular momentum is not a quantum number and changes with the magnetic field strength.Comment: 10 pages, 17 figure

PHOTOLUMINESCENCE STUDIES OF n-TYPE MODULATION DOPED AlGaAs-GaAs MULTIPLE QUANTUM WELLS IN TILTED MAGNETIC FIELDS

We have investigated the effect of tilted magnetic fields on the energetics and the intensity of the photoluminescence in n-type modulation doped AlGaAs-GaAs multiple quantum well structures. Combined resonance excitations are observed ; the data can be analyzed into contributions from field components parallel and perpendicular to the surface normal. Effective masses in the two orthogonal directions can be deduced. The overall luminescence efficiency increases with magnetic field for all orientations but is greater for axial fields than for radial fields