19 août 2019

[Thin films] – Crystalline GaAs Thin Film Growth on a c-Plane Sapphire Substrate

Accueil / Actualités / [Thin films] – Crystalline GaAs Thin Film Growth on a c-Plane Sapphire Substrate
Flèche contenu
Crystalline AsGa thin film Growth - Codex International

Crystalline zinc blende GaAs has been grown on a trigonal c-plane sapphire substrate by molecular beam epitaxy. The initial stage of GaAs thin film growth has been investigated extensively in this paper. When grown on c-plane sapphire, it takes (111) crystal orientation with twinning as a major problem. Direct growth of GaAs on sapphire results in three-dimensional GaAs islands, almost 50% twin volume, and a weak in-plane correlation with the substrate. Introducing a thin AlAs nucleation layer results in complete wetting of the substrate, better in-plane correlation with the substrate, and reduced twinning to 16%. Further, we investigated the effect of growth temperature, pregrowth sapphire substrate surface treatment, and in-situ annealing on the quality of the GaAs epilayer. We have been able to reduce the twin volume below 2% and an X-ray diffraction rocking curve line width to 223 arcsec. A good quality GaAs on sapphire can result in the implementation of microwave photonic functionality on a photonic chip.

Découvrez aussi
[Nano-Medecine] – The Discovery of Stem Cells Through Confocal Microscopes 12 novembre 2019

The plasticity of embryonic stem cells is widely understood; however, adult stem cells have traditionally been considered less capable of this same characteristic. To confirm whether this assumption is valid, and ultimately to identify any adult stem cells that can be induced into distinct types of cells, researchers have turned to confocal microscopy.

Lire la suite
[Nanotechnology] – How manipulating ligand interactions in metal clusters can spur advances in nanotechnology 23 février 2020

When metal atoms form small clusters of a particular size, they show interesting and potentially useful electromagnetic characteristics, which are different from those of the actual bulk metal. To fully explore the potential of these properties, it is necessary to find ways to assemble precise macroscopic structures out of these clusters.

Lire la suite