Final PhD Seminar-InP Nanowires Grown by Selective-Area Metalorganic Vapour Phase Epitaxy”
Semiconductor nanowires have attracted significant attention over the past decade. In particular, InP nanowires are promising because InP is a direct bandgap material and has high electron mobility, which makes it one of the most suitable material for many electronic and optoelectronic devices. Selective-Area Metalorganic Vapour Phase Epitaxy (SA-MOVPE) is one of the versatile and powerful techniques for growing nanowires due to the advantages of being catalyst free, and its ability to produce position controlled nanowires with high uniformity and better reproducibility. Therefore, InP nanowires grown by SA-MOVPE are highly desirable for future nano-scale device applications.
In this talk, I will present my work on growing stacking-fault-free and taper-free wurtzite InP nanowires with a wide range of diameters using SA-MOVPE. This involves a systematic investigation of the growth conditions like growth temperature and precursor flow rates. The morphology, crystal structure and optical properties of these InP nanowires are investigated and a detailed growth study revealing the fundamental growth mechanisms will be presented. Room temperature lasing from conventional guided modes in these nanowires has been demonstrated due to their uniform structure and high quantum efficiency. After that, I will present my work on growing and characterising doped InP nanowires. A newly developed optical method to study nanowire doping concentration and internal quantum efficiency will be presented. Finally, axial p-i-n InP nanowire array solar cells have been fabricated and characterised. Electron beam induced current measurement is used to visualize the width and position of the p-n junction for device optimisation.