On the quantum and classical scattering times due to charged dislocations in an impure electron gas

We derive the ratio of transport and single particle relaxation times in three and two - dimensional electron gases due to scattering from charged dislocations in semiconductors. The results are compared to the respective relaxation times due to randomly placed charged impurities. We find that the ratio is larger than the case of ionized impurity scattering in both three and two-dimensional electron transport.Comment: 4 pages, 3 figure

Variational Calculation for Triangular Quantum Wells Using Modified Trial Wave Function

In calculations involving triangular quantum wells the Fang-Howard variational wave function is widely used because of its simplicity, although it can lead to substantial errors. This can also occur in transport calculations, where the scattering rate, being proportional to the integral of the fourth power of the wave function, depends strongly on the shape of the wave function. A new set of one-parameter wave functions is introduced and the relaxation time is evaluated for short range scatterers. The improved wave function leads up to about 22 per cent increase in the scattering rate, and to a comparable decrease in the relaxation time

Far-infrared lattice absorption in gallium phosphide

The far-infrared lattice absorption in gallium phosphide was measured using a Fourier-transform spectrometer at 300 and 100 K. Two-phonon combination (difference) and overtone bands were identified in the spectral range 30-300 cm-1. The observed features were assigned on the basis of zone-edge phonon pairs at X, L, W and K points.L'absorption en infrarouge lointain dans le réseau de phosphure de gallium a été mesurée en utilisant un spectromètre à transformée de Fourier à 300 et 100 K. Des combinaisons à 2 phonons (soustraction et addition) ont été observées dans la bande spectrale 30-300 cm-1. Les caractéristiques observées sont attribuées, sur la base de paires de phonons proches des limites de la zone de Brillouin, aux points X, L, W et K

Photoluminescence and Double-Crystal X-Ray Study of InGaAs/InP: Effect of Rare Earth (Dysprosium) Addition During Liquid Phase Epitaxial Growth

High purity In$\text{}_{0.53}$Ga$\text{}_{0.47}$As layers were grown on semi-insulating InP:Fe substrates by liquid phase epitaxy by adding small amounts of dysprosium (rare earth) to the melt. Hall effect and photoluminescence measurements showed that the addition of Dy strongly reduced the carrier and residual donor concentration, with a concurrent shift of the excitonic luminescence toward higher energies. The observed effects are ascribed to the gettering of residual donor impurities in the melt by Dy, as well as to the effects of possible incorporation of Dy into the grown layers

Observations on residual donors in GaP LPE

Electron and donor concentrations and mobilities of non doped liquid phase epitaxial GaP layers were studied when varying the annealing process prior to growth. Main donors or the presence of more than one donor were identified by donor ionization energies. After short anneallings the incorporation of sulphur, after long annealings the incorporation of silicon were observed

Wigner Crystallization in InGaAs/InP Heterostructures with a Strong Disorder

Non-linear current-voltage characteristics were observed in the range of filling factors of 0.3 ≤ v ≤ 0.4 in a two-dimensional electron system in InGaAs/InP heterostructures with a strong disorder. The observations are explained qualitatively in terms of magnetic field induced localization and Wigner solidification