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Semiconductor Layer (semiconductor + layer)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Physics and Astronomy	50%

Selected Abstracts

Interface Modification to Improve Hole-Injection Properties in Organic Electronic Devices,

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006
A. Choulis
Abstract The performance of organic electronic devices is often limited by injection. In this paper, improvement of hole injection in organic electronic devices by conditioning of the interface between the hole-conducting layer (buffer layer) and the active organic semiconductor layer is demonstrated. The conditioning is performed by spin-coating poly(9,9-dioctyl-fluorene- co - N - (4-butylphenyl)-diphenylamine) (TFB) on top of the poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) buffer layer, followed by an organic solvent wash, which results in a TFB residue on the surface of the PEDOT:PSS. Changes in the hole-injection energy barriers, bulk charge-transport properties, and current,voltage characteristics observed in a representative PFO-based (PFO: poly(9,9-dioctylfluorene)) diode suggest that conditioning of PEDOT:PSS surface with TFB creates a stepped electronic profile that dramatically improves the hole-injection properties of organic electronic devices. [source]

Molecular Self-Assembled Monolayers and Multilayers for Organic and Unconventional Inorganic Thin-Film Transistor Applications

ADVANCED MATERIALS, Issue 14-15 2009
Sara A. DiBenedetto
Abstract Principal goals in organic thin-film transistor (OTFT) gate dielectric research include achieving: (i) low gate leakage currents and good chemical/thermal stability, (ii) minimized interface trap state densities to maximize charge transport efficiency, (iii) compatibility with both p- and n- channel organic semiconductors, (iv) enhanced capacitance to lower OTFT operating voltages, and (v) efficient fabrication via solution-phase processing methods. In this Review, we focus on a prominent class of alternative gate dielectric materials: self-assembled monolayers (SAMs) and multilayers (SAMTs) of organic molecules having good insulating properties and large capacitance values, requisite properties for addressing these challenges. We first describe the formation and properties of SAMs on various surfaces (metals and oxides), followed by a discussion of fundamental factors governing charge transport through SAMs. The last section focuses on the roles that SAMs and SAMTs play in OTFTs, such as surface treatments, gate dielectrics, and finally as the semiconductor layer in ultra-thin OTFTs. [source]

Rashba spin,orbit effect on shot noise in ferromagnetic/semiconductor/ferromagnetic heterojunctions

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 14 2005
Ying-Tao Zhang
Abstract Using the scattering approach, shot noise in ferromagnetic/semiconductor/ferromagnetic heterjunctions in the presence of Rashba spin,orbit interaction has been studied theoretically. The quantum size effect, degree of spin-polarization, and Rashba spin,orbit interaction are considered simultaneously. The results indicate that the Fano factors for spin-polarized electrons oscillate strongly due to the influence not only of the Rashba spin,orbit coupling but also of the length of the semiconductor layer. For a certain length of semiconductor, the Fano factors can be determined by the strength of the Rashba spin,orbit coupling. Further, it is found that the higher the degree of spin-polarization, the larger the Fano factors. These results may be useful in the measurement of Rashba spin,orbit coupling via shot noise. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A theoretical investigation of carrier and optical mode confinement in GaInNAs QWs on GaAs and InP substrates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007
B. Gönül
Abstract Both carrier and optical mode confinements are the basic ingredients while designing the semiconductor quantum well lasers. The former strongly depends on the band offsets of the heterostructure and the latter is mainly associated with the difference in the refractive index between the wave guiding core and the cladding layers. It is known that refractive index strongly depends on the direct band gap of the semiconductor material and the band gap of the III-N-V semiconductor layer can be engineered by means of adding nitrogen into InGaAs. We investigate, in this work, the refractive indices and the corresponding optical confinement factors of the proposed III-N-V laser material systems on GaAs and InP substrates. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Oxidation treatment on Ni/Au Ohmic contacts to p-type GaN

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2003
Z. Z. Chen
Abstract Current,voltage (I,V) characteristics, transmission line method (TLM), and optical transmittance measurements are performed to investigate the effects of thermal oxidation and plasma-induced oxidation treatments on Ni/Au contacts to p-type GaN. Whether oxidation and thermal annealing are performed simultaneously or in succession, the specific contact resistances of Au/Ni/p-GaN are reduced. As to plasma-induced oxidation, neither no-oxidation nor long-time oxidation treatments on Ni/Au layers are suitable for obtaining a low-resistance Ohmic contact. The roles of oxidation are believed to activate the Mg acceptor in p-GaN and to form an oxygenous intermediate semiconductor layer, which may lower the Schottky barrier height between the metal layer and p-GaN. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Versatile Use of Vertical-Phase-Separation-Induced Bilayer Structures in Organic Thin-Film Transistors,

ADVANCED MATERIALS, Issue 6 2008
Longzhen Qiu
A semiconductor-top and dielectric-bottom bilayer structure is fabricated by surface-induced vertical phase separation of poly(3-hexylthiophene) (P3HT) and poly(methyl methacrylate) (PMMA) blends (see figure). This structure allows to prepare high-performance, low-semiconductor-content, and low-voltage-driven TFTs in a very effective method, in which the dielectric and semiconductor layers are deposited onto a substrate in a one-step process. [source]