Group III-nitride nanowires are considered as promising building blocks for highly efficient optoelectronic devices thanks to their ideal bandgaps, high aspect ratio, high crystal quality and the possibility for axial/radial heterostructures enabling tunable optical emission, ranging from the deep ultraviolet (AlN) to the near infrared (InN). Among these nanowires, self-assembled GaN wires are gaining increasing attention due to the simplicity in sample preparation and the foreign-catalyst-free approach used for their synthesis. The self-assembled process is also highly practical for a range of applications not requiring precise positioning, such as single wire devices and flexible nanowire light emitting diodes (LEDs).
In this talk, I will present my work on self-assembled GaN wires grown on sapphire substrates using metalorganic chemical vapour deposition (MOCVD). This involves a systematic investigation of the influence of various growth conditions like temperature, precursor flows rates and chamber pressure at different stages of the growth process. The study of morphology and optical properties of GaN rods will be discussed in detail. Then I will present the study on the InGaN/GaN multi-quantum well (MQW) core-shell structures, which is promising for LED applications. Finally, the results on selective-area epitaxy of GaN nanowires will be also be presented.