Papers by Keyword: Defects in Semiconductors

Abstract: Accelerator-based nuclear techniques are an important tool for the modification and characterization of surfaces in general, down to a depth of around one micrometer. For oxide semiconductors used in solar energy conversion, the surface plays a critical role in facilitating the use of solar photon energy to obtain hydrogen via spontaneous water oxidation. For such a process, the required surface properties are complex and include specific chemical composition, as well as the defect composition, and both of these characteristics may be augmented using accelerator-based nuclear techniques. The targeted modification of surfaces makes use of ion implantation for changing the chemical composition, and ion irradiation for changing the defect structure. The defect formation is a very complex process, and in this work we placed more emphasis on this aspect. We attempted to present the defect formation under the irradiation of ion beams at the two extremes: formation of extensive and large-scale cluster defects; and formation of small-scale point defects. In addition, we review the main characterization techniques based on ion beams, with examples from work carried out on semiconductors and oxide semiconductors.

Abstract: Protons with energies of 1 MeV and 2.5 MeV were implanted into a p-doped silicon wafer and then the wafer was annealed at 350 °C for one hour. This resulted in two n-doped layers in the otherwise p-doped sample. The carrier concentration was measured using spreading resistance profiling while the positions of the four pn-junctions were measured using electron beam induced current measurements. The carrier concentration is not limited by the available hydrogen but by the concentration of suitable radiation induced defects.