19 août 2019

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

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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] – Nanotechnology and the Future of the Beverage Industry 25 octobre 2020

The rapid increase in the world’s population has subsequently increased the demand for food supply. Farmers often lose their agricultural produce due to pathogenic infestations, poor soil conditions, water, and environmental factors. Scientists believe nanobiosensors can play a crucial role in revolutionizing the farming system by determining threats to prevent agricultural loss.

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[UHV] – Sample Transfer in UHV Applications 3 novembre 2020

Certain areas of scientific research require atomically clean surfaces and low rates of contamination. In these instances, the ultra-high vacuum (UHV) environments are essential.

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