Synchrotron x-ray topographic and high-resolution diffraction analysis of mask-induced strain in epitaxial laterally overgrown GaAs layers

Synchrotron x-ray back reflection section topographs of epitaxial lateral overgrown (ELO) GaAs samples grown on (001) GaAs substrates show images of the GaAs layers bent due to the interaction between the layer and the SiO2 mask. The topographs are simulated under the assumption of orientational contrast. Using the same data the measured x-ray diffraction curve is simulated. The calculations, which are in good agreement with the measurements, are used to gain information on the tilted (001) lattice planes in each ELO layer. We show that the bending of ELO lattice planes reaches a maximum at the center of the ELO stripes, where misorientation is at a minimum, and decreases towards the edges of the stripes, where misorientation reaches a maximum

Photoinduced defects creation on sulfur passivated surface of GaAs

We report on photoinduced defect creation on the sulfurized (100) GaAs surface. The process manifests itself by unrecoverable temporal decrease in the photoluminescence intensity of the GaAs surface treated by (NH4)2Sx solution. The results are discussed in terms of a photoinduced process of the AsGa antisite generation on the sulfurized surface of GaAs.Peer Reviewe

Epitaxial Lateral Overgrowth - a Tool for Dislocation Blockade in Multilayer Systems

Results on epitaxial lateral overgrowth of GaAs layers are reported. The methods of controlling the growth anisotropy, the effect of substrate defects filtration in epitaxial lateral overgrowth procedure and influence of the mask on properties of epitaxial lateral overgrowth layers will be discussed. The case of GaAs epitaxial lateral overgrowth layers grown by liquid phase epitaxy on heavily dislocated GaAs substrates was chosen as an example to illustrate the processes discussed. The similarities between our results and those reported recently for GaN layers grown laterally by metallorganic vapour phase epitaxy will be underlined

Electroepitaxial Growth of GaSb and AlGaSb Thick Epitaxial Layers

Semi-bulk epitaxial layers of GaSb and AlGaSb up to 3 and 1 mm thick, respectively, were successfully grown by the liquid phase electroepitaxy on GaSb substrates. The growth procedure allowed us to achieve high crystallographic perfection as well as compositional uniformity of ternary layers

High-temperature ultraviolet detection based on surface photovoltage effect in SiN passivated n-GaN films

We investigated the surface photovoltage (SPV) effect in n-GaN layers passivated with various insulators, i.e., Al2O3, SiO2, and SiN for ultraviolet (UV) light detection. We revealed that SPV in SiN/GaN shows markedly different behaviour than in oxide/GaN, i.e., the photo-signal exhibited very fast response (1 s) and recovery (2 s) times, contrary to oxide/GaN, and it was thermally stable up to 523 K. Furthermore, SPV spectra for SiN/GaN showed a sharp cut-off edge directly corresponding to the GaN band gap. We explained these results in terms of the different band structure of SiN/GaN and oxide/GaN junctions. All the observed properties of SPV response from SiN/GaN indicate that this relatively simple system can be applied to sensitive high temperature visible-blind UV detection. Published by AIP Publishing

Synchrotron x-ray topography analysis of GaAs layers grown on GaAs substrates by liquid phase epitaxial lateral overgrowth

Synchrotron x-ray topography techniques in section and back-reflection geometries have been applied to silicon and tin doped GaAs layers grown by the liquid phase epitaxial lateral overgrowth (ELO) technique on (100) GaAs substrates. Back-reflection topographs show that the laterally grown parts of the ELO layers are nearly dislocation free in spite of a large density of defects in the substrate. Section topographs reveal novel and unique features which are attributed to the bending of the ELO layers induced by their interaction with the SiO2 mask