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Semiconductor Thin Films (semiconductor + thin_film)
Kinds of Semiconductor Thin Films Selected AbstractsDewetting of an Organic Semiconductor Thin Film Observed in Real-time,ADVANCED ENGINEERING MATERIALS, Issue 4 2009Stefan Kowarik We study the growth and the post-growth dewetting process of the organic semiconductor diindenoperylene (DIP) using real-time X-ray reflectivity measurements. We show that a DIP monolayer deposited in UHV onto silicon oxide dewets via the formation of bilayer islands. From the time resolved structural data we estimate the rate constant for interlayer diffusion of DIP molecules. Post-growth AFM measurements confirm the conclusions from the X-ray data and show the morphology of the dewetted film. [source] Control of the Morphology and Structural Development of Solution-Processed Functionalized Acenes for High-Performance Organic TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 10 2009Jung Ah Lim Abstract Solution-processable functionalized acenes have received special attention as promising organic semiconductors in recent years because of their superior intermolecular interactions and solution-processability, and provide useful benchmarks for organic field-effect transistors (OFETs). Charge-carrier transport in organic semiconductor thin films is governed by their morphologies and molecular orientation, so self-assembly of these functionalized acenes during solution processing is an important challenge. This article discusses the charge-carrier transport characteristics of solution-processed functionalized acene transistors and, in particular, focuses on the fine control of the films' morphologies and structural evolution during film-deposition processes such as inkjet printing and post-deposition annealing. We discuss strategies for controlling morphologies and crystalline microstructure of soluble acenes with a view to fabricating high-performance OFETs. [source] Cover Picture: A Novel Method to Orient Semiconducting Polymer Films (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 7 2005Mater. Abstract A new technique for orienting thin polymer semiconductor films is reported by Österbacka and co-workers on p.,1095. The technique uses the mechanical force of a shrinking polymer transferred through a polymer multilayer structure. The orientation is obtained using three polymer layers, where the uppermost layer shrinks resulting in orientation of the semiconductor film beneath the intermediate layer. The topmost and intermediate polymer films are removed to reveal the oriented surface. The cover shows a crossed-polarizer microscopy image of an oriented regio-regular poly(3-hexylthiophene) film. We present a new technique for orienting polymer semiconductor thin films. In our technique, polymer chains are rigorously oriented without using any mechanical tools and with minimal risk of film contamination. The technique is based on the mechanical force resulting from the in-plane shrinkage exerted by a shrinker (top layer) that is used to orient the semiconductor beneath an intermediate layer; the latter acting as a force mediator. The chain orientation is demonstrated by several techniques such as crossed-polarizer microscopy, atomic force microscopy, grazing-incidence X-ray diffraction, and polarized absorption. The orientation geometry is controlled by the shrinking process and the shrinker area. The semiconductivity of the film only stems from the transistor device structures under study, and the method can therefore be generalized. [source] Organic Thin-Film Transistors: Controlling Nucleation and Crystallization in Solution-Processed Organic Semiconductors for Thin-Film Transistors (Adv. Mater.ADVANCED MATERIALS, Issue 35 200935/2009) The grain size in solution-processed organic semiconductor thin films for TFTs can be tuned over a range of three orders of magnitude, report Yueh-Lin Loo and co-workers on p. 3605. The process involves the addition of fractional quantities of "impurities" that are capable of seeding the crystallization of the organic semiconductor, and the control thus exerted permitted studies that correlated increasing device mobility with increasing grain size. [source] Controlling Nucleation and Crystallization in Solution-Processed Organic Semiconductors for Thin-Film TransistorsADVANCED MATERIALS, Issue 35 2009Stephanie S. Lee Three orders of magnitude is the range over which the grain size (see figure) can be tuned in solution-processed organic semiconductor thin films for TFTs. Fluorinated triethylsilyl anthradithiophene (FTES-ADT) is added in fractional amounts to seed crystallization of TES-ADT. Correlation between device mobility and grain size in the active layer is described by a composite mobility model that assumes charge-carrier traps are located at grain boundaries. [source] Elastic constants of aluminum nitridePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007M. Kazan Abstract We report on the application of Brillouin spectroscopy as an approach to non-destructive optical characterization of the elastic constants of semiconductors with the wurtzite symmetry. Three different configurations were used to achieve a complete determination of the elastic stiffness constants of bulk AlN substrates grown by the Physical Vapor Transport (PVT) method. The scattering diagrams of these three configurations are presented showing the geometrical arrangements necessary to observe all the elastic stiffness constants for the partially nontransparent wurtzite type of the crystal structure. Because aluminum nitride (AlN) is a suitable material for the fabrication of light emitting devices, the characterization of its elastic constants was carried out very precisely to provide a reliable data which can be used for the determination of residual stress arising during the growth of AlN thin films or wide band gap semiconductor thin films on substrates of AlN. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] |