Towards a Classification of the Effects of Disorder on Materials Properties

Many 'interesting; correlated electron materials exhibit an unusual sensitivity of measured properties to external perturbations, and in particular to imperfections in the sample being measured. It is argued that in addition to its inconvenience, this sensitivity may indicated potentially useful properties. A partial classification of causes of such sensitivity is given.Comment: Solid State Communications, in press (Proceedings of the June 2002 Williamsburg conference on Muon Spin Rotation

Field Effect Transistors on Rubrene Single Crystals with Parylene Gate Insulator

We report on fabrication and characterization of the organic field effect transistors (OFETs) on the surface of single crystals of rubrene. The parylene polymer film has been used as the gate insulator. At room temperature, these OFETs exhibit the p-type conductivity with the field effect mobility up to 1 cm^2/Vs and the on/off ratio ~ 10^4. The temperature dependence of the mobility is discussed.Comment: 3 page

Organic Single-Crystal Field-Effect Transistors

We present an overview of recent studies of the charge transport in the field effect transistors on the surface of single crystals of organic low-molecular-weight materials. We first discuss in detail the technological progress that has made these investigations possible. Particular attention is devoted to the growth and characterization of single crystals of organic materials and to different techniques that have been developed for device fabrication. We then concentrate on the measurements of the electrical characteristics. In most cases, these characteristics are highly reproducible and demonstrate the quality of the single crystal transistors. Particularly noticeable are the small sub-threshold slope, the non-monotonic temperature dependence of the mobility, and its weak dependence on the gate voltage. In the best rubrene transistors, room-temperature values of $\mu$ as high as 15 cm$^2$/Vs have been observed. This represents an order-of-magnitude increase with respect to the highest mobility previously reported for organic thin film transistors. In addition, the highest-quality single-crystal devices exhibit a significant anisotropy of the conduction properties with respect to the crystallographic direction. These observations indicate that the field effect transistors fabricated on single crystals are suitable for the study of the \textit{intrinsic} electronic properties of organic molecular semiconductors. We conclude by indicating some directions in which near-future work should focus to progress further in this rapidly evolving area of research.Comment: Review article, to appear in special issue of Phys. Stat. Sol. on organic semiconductor

Beam waist measurement for terahertz time-domain spectroscopy experiments

International audienceClassical masking aperture methods are found to be mostly inaccurate to determine the terahertz beam size in terahertz time-domain spectroscopy (TDS) experiments, owing to complex diffraction effects. Here, we present a simple and reliable method for measuring beam waists in terahertz TDS. It is based on the suecessive diffraction by an opaque disk followed by a small circular aperture. Cop. 2010 Optical Society of America

Extended fano model of extraordinary electromagnetic transmission through subwavelength hole arrays in the terahertz domain

International audienceWe developed an extended Fano model describing the Extraordinary Electromagnetic Transmission (EET) through arrays of subwavelength apertures, based on terahertz transmission measurements of arrays of various hole size and shapes. Considering a frequency-dependent coupling between resonant and non-resonant pathways, this model gives access to a simple analytical description of EET, provides good agreement with experimental data, and offers new parameters describing the influence of the hole size and shape on the transmitted signal. Cop. 2009 Optical Society of America