Bachelor Thesis from the year 2011 in the subject Physics - Other, grade: 1,0, LMU Munich, language: English, abstract: In this thesis the InAs(111)B surface and III-V semiconductor nanowires are investigated using scanning tunneling microscopy and spectroscopy. The morphology of InAs nanowires grown without gold particle is studied. Radial nanowire heterostructure such as InP core with InAs shell are analyzed and the wurtzite top facet is identified. Furthermore nanowire heterostructures with an InP core and InAs shell with induced stacking faults possibly giving rise to quantum dots, which could be used as quantum dot lasers or for quantum information processing, are investigated. A model is obtained based on morphology analysis and as top facet the wurtzite and are found. Furthermore stacking faults on top of a nanowire are seen. The analysis of the InAs(111)B surface shows the hexagonal pattern. Defects are determined to occur due to missing In atoms in the first layer. Spectroscopy next to those defects indicated no influence on the local electronic structure.