Growth and characterization of III-V phosphide nanowires

Nanowires are 1D rod-like structures which are regarded as the basis for future technologies. III-V nanowires have attracted immense attention because of their stability, crystal quality and wide use. In this work, I focus on the growth and characterization of III-V semiconductor nanowires, in particular GaP, InP and InGaP alloys. These nanowires were grown using a hot wall CVD(Chemical Vapor Deposition) setup and are characterized using SEM (Scanning Electron Microscope), EDX (Energy Dispersive X-ray Spectroscopy) and PL (Photoluminescence) techniques.



In the first chapter, Indium Phosphide nanowires were grown using elemental sources (In and P powders). I consider the various kinds of InP morphologies grown using this method. The effect of source temperature on the stoichiometry and optical properties of nanowires is studied. Lasing behavior has been seen in InP nanostructures, showing superior material quality of InP.

InGaP alloy nanowires were grown using compound and elemental sources. Nanowires grown using compound sources have significant oxide incorporation and showed kinky morphology. Nanowires grown using elemental sources had no oxide and showed better optical quality. Also, these samples showed a tunable alloy composition across the entire substrate covering more than 50% of the InGaP alloy system. Integrated intensity showed that the bandgap of the nanowires changed from indirect to direct bandgap with increasing Indium composition. InGaP alloy nanowires were compared with Gallium Phosphide nanowires in terms of PL emission, using InGaP nanowires it is possible to grow nanowires free of defects and oxygen impurities, which are commonly encountered in GaP nanowires.