Nanomaterials and Nanotechnology

Biography

Biography: Abdallah Ougazzaden

Abstract

Nanostructures based on wide bandgap III-nitrides have recently emerged as one of the most promising class of material for site-controlled opto-electronic and nanophotonics devices. But growing high quality thick III-nitride alloys like InGaN, BGaN and AlGaN is challenging due to lattice mismatch induced phase separation, defects and dislocations. Nanoselective area growth (NSAG) of GaN, InGaN and BGaN nanopyramids on GaN template, Si substrates and sacrificial-ZnO/Al2O3 was investigated to mitigate the above issues. Nanopatterned SiO2 with 100 nm circular openings was made using E-beam lithography. Growth of thick InGaN and BGaN was carried out by MOCVD on silicon substrates and ZnO templates. This nano bottom-up approach leads to dislocation free nanostructures due to the three dimensional stress relief mechanisms. In stark contrast to the conventional epilayers, which contain 3D surfaces, huge density of defects and V-pits network, the GaN, InGaN and BGaN nanopyramids are uniformly sized and hexagonal in shape. Cross sectional STEM analysis confirms that these nanopyramids are single crystalline and free from threading dislocations. Full PIN structures were grown sandwiching the InGaN nanopyramids on GaN templates. Further 2D layered BN on 2” sapphire wafers were realized for the first time to serve as a platform for combining graphene nanoelectronics with III-nitride nanophotonic components. Given their expected high performances and lifetime, along with their industrial maturity for light-emitting diode (LEDs) applications, such alloy nanostructures are appealing for new generation of optoelectronc devices. New designs and device structures for high efficiency solar cells, µ-LEDs, gas and water sensors will be presented.