Winner of the Competition “Prize for PhD thesis 2015”
Semiconductor nanowires (NWs) are promising building blocks of next-generation electronics, photonics, biosensing, and solar cell devices. The name NWs derives from their filamentary shape: NWs have diameter of tens of nanometers and are few microns long. Since 1990, when the word ‘nanowire’ first appeared in a paper, NWs have inspired many scientists around the world, for their capability to provide a natural bridge between macroscopic and microscopic worlds. In fact, NWs are smaller than bulk crystals and larger than zero-dimensional nanocrystals.
If NWs have to be a central task in technological applications, a full understanding of their properties is required. This work indeed aimed at determining the fundamental electronic properties of the most technologically relevant III-V NWs (GaAs, InGaAs, and InP). Optical and magneto-optical spectroscopies allowed to establish: i ) the characteristics of light absorption processes involved in the design of NW-based solar cells; ii ) the electronic band structure of NWs in the wurtzite crystal structure, which is uniquely found in NW materials and is relevant for light polarization-sensitive opto-electronic devices; iii ) the transport and spin properties of NWs and their dependence on chemical composition, crystal structure and magnetic field direction, that are issues addressed for the first time in the present work.