Transmission electron microscopy and reflected high-energy electron-diffraction investigation of plastic relaxation in doped and undoped ZnSe/GaAs(001)

Abstract

We report on reflected high-energy electron-diffraction and transmission electron microscopy plane-view investigation of the dislocation structure in doped and undoped ZnSe/GaAs(001) grown by molecular-beam epitaxy and metal-organic vapor-phase epitaxy. The thicknesses of the investigated layers vary between 60 and 900 nm. Several stages of dislocation formation are found which occur at distinct layer thicknesses. Frank partial dislocations (up to 500 nm), Shockley partial dislocations (between 130 and 400 nm) with a maximum density at 300 nm, and perfect 60° dislocations (above 300 nm) are observed in samples with perfectly smooth surface. The formation of Shockley partial dislocations is strongly anisotropic which might be due to the higher mobility of α-type dislocations. An increased roughness of the growing surface yields a suppression of Shockley partial dislocations and an irregular dislocation network with dislocations inclined to the 〈110〉 directions. A regular dislocation network with straight dislocations is found in Cl-doped samples.

Quantum dots formed by ultrathin insertions in wide-gap matrices

“…In Fig. 1 we show a processed HRTEM image obtained using DALI procedure [30] for a stacked SML±CdSe/ZnMgSSe structure with 30 A Ê spacer thickness. A color-coded map corresponding to the local lattice parameter in growth direction is shown.…”

Island formation and dynamics of gold clusters on amorphous carbon films

“…The electrostatic potential of the biprism wire was close to 150 V. The images recorded were analyzed using the phase shift of the (000)-beam of the first hologram sideband. Data analysis was performed using the DALI program package, 31 which was extended for the reconstruction of holograms. The details of the reconstruction of holograms are outlined by Lichte and Lehmann.…”

High-Resolution Electron Microscopy of Semiconductor Heterostructures and Nanostructures

“…Peak-finding techniques were first described by Bierwolf et al [24] and further developed by Jouneau et al [25], Seitz et al [26], Kilaas et al [27], Robertson et al [28], and Rosenauer et al [29]. All these techniques were based on superimposing a two-dimensional reference lattice extrapolated from a non-distorted region of the material to the experimental one, built up from the set of intensity maxima in the HRTEM image, and calculating the local discrete displacement field at each node [30].…”