This thesis investigates a range of surface and interface preparation procedures for the ternary III-V semiconductor, InGaAs which has potential applications in high speed metal-oxide-semiconductor field effect transistors (MOSFETs). Various chemical methods of passivating the InGaAs surface prior to high-k dielectric deposition have been studied. Both conventional x-ray photoelectron spectroscopy (XPS) and high resolution synchrotron radiation based photoemission spectroscopy (HSRPES) have been used to investigate the chemical interactions at the high-k/InGaAs interface while electrical characterisation studies have been made by current-voltage (I-V) and capacitance-voltage (C-V) measurements. A systematic study of in-situ sulphur passivation of the atomically clean InGaAs surface has been performed and a comparison has been made with wet chemical ex-situ preparations methods. High temperature thermal stability experiments were also performed to establish a threshold decomposition temperature for these surfaces. In addition, high temperature thermal stability studies were carried out on interfaces between ultrathin atomic layer deposited (ALD) Al2O3 layers and differently prepared InGaAs surfaces. The interface formation between an in-situ deposited MgO dielectric layer and the atomically clean InGaAs surface was studied by high resolution synchrotron radiation based photoemission. Finally, the effectiveness of the insertion of ultrathin ALD deposited Al2O3 dielectric layers on the Schottky barrier formed at the interface between different work function metals and the InGaAs surface was also investigated.