
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.
Discover AlsoResearchers from the Nanophotonic Technology Centre (NTC) of the Polytechnic University of Valencia (UPV) have designed new silicon nanoantennas with direct applications in communication and data processing for the next generation of reconfigurable photonic chips.
Read moreCopper has been essential to human technology since its early days–it was even used to make tools and weapons in ancient times. It is widely used even today, especially in electronic devices that require wiring.
Read more