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Hydrogenated nanocrystalline silicon (nc-Si:H) is a multiphase, heterogeneous material, composed of Si nanocrystals embedded in an amorphous matrix. It has been intensively studied recently due to very promising photovoltaic and optoelectronics applications. The present paper aims to study electronic transitions in nc-Si:H grown by Low Energy Plasma Enhanced Chemical Vapor Deposition by Surface Photovoltage Spectroscopy. The study of several thin films grown at different conditions and the comparison with recently published computational studies allowed us to advance a hypothesis on the defect structure responsible for electronic transitions in nc-Si:H. [ABSTRACT FROM AUTHOR]

Silk is a natural biocompatible material that can be integrated in a variety of photonic systems and optoelectronic devices. The silk replication of patterned substrates with features down to tens of nanometers is exploited to realize highly transparent, mechanically stable, and free-standing structures with optical wavelength size. We demonstrate organic lasing from a blue-emitting stilbene-doped silk film spin-coated onto a one-dimensional distributed feedback grating (DFB). The lasing threshold is lower than that of organic DFB lasers based on the same active dye. These findings pave the way to the development of an optically active biocompatible technological platform based on silk. [ABSTRACT FROM AUTHOR]

We describe a setup suitable for simultaneously measuring optical and electrical properties of a liquid crystal mesophase upon temperature variation, and the difference in the order parameters between the bulk and the interface with the substrate. It integrates high-resolution polarized light optical microscopy, temperature regulation, and electrical measurements in a controlled atmosphere with a software kernel that controls the instruments and synchronizes the data streams. A user-friendly interface allows us to program multistep experiments controlling all the instruments and data acquisition by a specifically designed scheduler. We tested our system on a thin film of alkoxy-substituted phthalocyanines deposited on a test pattern with interdigitated electrodes. We studied the optical and electrical behavior in the proximity of the bulk phase transition to isotropic liquid, identifying a few ordered monolayers anchored to the substrate above the transition temperature. [ABSTRACT FROM AUTHOR]

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]

In this work the authors report on photocurrent spectroscopy analyses on pentacene thin film transistors that have been bias stressed and exposed to atmosphere over a long period of time (up to 80 days). They have studied the charge transport properties and the electronic excited state energy and distribution of these organic thin film devices. They also have identified the major excitonic and band gap transition energies and have investigated their quite different behavior following exposure to atmosphere or to bias stress. Different charge carrier distributions and trapping phenomena are proposed to describe the observed effects. [ABSTRACT FROM AUTHOR]