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Abstract: Hydrogenated nanocrystalline silicon (nc-Si:H) is a very promising material for photovoltaic applications. Notwithstanding its wide application as instrinsic layer in solar cells, many issues regarding its electronic and optical properties are not completely understood. The influence of crystal defects and impurities on the physical properties of nc-Si:H is not completely explored yet. The present contribution aims to report on defective states associated with crystal defects and impurities in nc-Si:H films grown by low-energy plasma enhanced chemical vapor deposition (LEPECVD) technique. Electronic levels associated to defect states were investigated by surface photovoltage spectroscopy (SPS) and the role of defects and impurities on the conduction mechanisms at a microscopic level were investigated by conductive atomic force microscopy (C-AFM). The results will be compared with structural analyses [Copyright &y& Elsevier]

AlInN/AlN/GaN heterostructures were characterized by atomic force microscopy. V-defects and channels were observed. In phase-contrast mode, these features were found related to inhomogeneities associated with In-segregation (and/or In-diffusion) and Al-rich surface reconstruction. The electrical characterization via conductive atomic force microscopy showed enhanced conductivity regions related to In-rich traces within channels and V-defects. [ABSTRACT FROM AUTHOR]

Abstract: The attainment of ultrathin films of well ordered II–VI and III–V compound semiconductors is an active research area of the electrochemistry group at the University of Florence. The method employed is the electrochemical atomic layer epitaxy (ECALE) which is based on self limiting reactions such as underpotential deposition (UPD). Recently, the possibility of combining the electrodeposition at nanometer scale and the self assembly phenomena has been investigated. In particular, the ECALE method was used to deposit CdS on Ag(111) covered by a patterned hexadecanthiol (HDT) self assembled monolayer (SAM). In fact, the deposition of CdS only takes place on the uncovered silver substrate, whereas it is not possible on the thiols monolayers. The deposits have been characterized by electrochemical techniques and AFM measurements. [Copyright &y& Elsevier]

Bottom contact FET devices were realized, using vacuum evaporated thin films of unsubstituted quinquethiophene and two modified derivatives deposited at different substrate temperatures. X-ray diffraction (XRD) and atomic force microscopy (AFM) data on thin films deposited in the same conditions are reported and related to the electrical characteristics of the devices. [Copyright &y& Elsevier]