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.

[Nanotechnology]- Estimating the occurrence of nanomaterials in the environment 12 septembre 2023

To perform a risk assessment of nanomaterials in the environment, information on the exposure, i.e. the amounts that are present in the environment, is essential. In contrast to many other known pollutants, the concentrations of nanomaterials in environmental systems cannot be measured directly. In this situation, exposure modelling is a solution to estimate the environmental exposure with synthetic nanomaterials.

Lire la suite
[Evènement] – Plathinium 2023 4 septembre 2023

Retrouvez-nous du 11 au 15 septembre 2023 à l’évènement mythique « Plathinium »

Lire la suite