The interest in InAs lays in its high electron mobility and small bandgap of 0.36eV which are useful properties for a range of devices, from high frequency transistors to quantum dot-based photodetectors. Experimental data characterizing the oxidation and surface properties are crucial for the design of devices that utilize these distinctive electrical properties because the oxide-semiconductor interface states and properties of the oxide are likely a large determinant of the properties of InAs’s native electron accumulation layer, or quasi-two-dimensional electron gas (2DEG). In many cases, the design of an InAs-based device relies on exploiting the accumulation layer; the key defects responsible for the Fermi-level pinning remain unknown but it is believed to be dependent upon a number of factors including composition, morphology, and the concentration of As- and In-based defects (J. R. Weber et al. Appl. Phys. Lett. 97, 192106 (2010)). Therefore, characterization of the surface Fermi energy and the 2DEG conductivity in relation to surface preparation, oxide composition, and morphology at the surface is critical knowledge. To investigate the relationship between oxide composition, In/As stoichiometry and Fermi energy at various near-surface depths, InAs samples were etched and terminated with either an As layer or 1 to 2 monolayers of In after in situ removal of the native oxide using Molecular Beam Epitaxy (MBE). Angle-resolved X-ray photoelectron spectroscopy (XPS) measurements determined the valence band maximum (VBM) and quantified the oxide composition and In/As stoichiometry at several depths (from 30, 45, 90 take-off angles). The XPS VBM data showed more extreme band bending occurring when terminated with In. Atomic force microscopy (AFM) determined an average roughness of 2-3nm and revealed a terraced surface with meandering step edges. The As-rich sample was rougher and the step features were twice the size. Van der Pauw (VdP) Hall measurements determined the mobility and carrier concentration. It is speculated that the trend in the mobility is due to a difference in the nature of predominate defects associated with the different oxide chemistries and their formation.