Field effect

About: Field effect is a research topic. Over the lifetime, 4018 publications have been published within this topic receiving 92613 citations.

The influence of mechanical rubbing on the field-effect mobility in polyhexylthiophene

Abstract: This paper reports on improvements of the field-effect mobility in regioregular head-to-tail coupled poly(3-hexylthiophene) based transistors by mechanically induced alignment of polymer chains in the active layer. It is demonstrated that mechanical rubbing perpendicular to the source drain contacts can increase the field-effect mobility up to 800% whereas rubbing parallel to the source drain contacts results in a reduced mobility. The polymer alignment is thereby deduced from optically polarized transmission spectroscopy on polymer-coated quartz glass substrates and is shown to directly correlate with the electrical behavior of a bottom-gate field-effect transistor. The influence of layer thickness on rubbing is investigated and it is shown that annealing after mechanical rubbing at high temperature can further increase the alignment. Differences between thick drop-cast and thin spin-coated films are explained in terms of different solvent evaporation rates, allowing the material to order to a different degree. This interpretation is deduced from characteristic optical and electrical features of the differently prepared poly(3-hexylthiophene) films.

Impact ionization in semiconductors: Effects of high electric fields and high scattering rates.

Abstract: We present a theory of impact ionization in semiconductors that expands an earlier theory of Kane and includes the effects of high electric fields and high scattering rates on the electron-electron collision process. We show that their combined effect, i.e., the intracollisional field effect and collision broadening, leads to a softening of the threshold energy for impact ionization and a marked increase in the anisotropy of the ionization rate with respect to the direction of the electric field.

Gate Capacitance-Dependent Field-Effect Mobility in Solution-Processed Oxide Semiconductor Thin-Film Transistors

Abstract: Solution-processed oxide semiconductors (OSs) used as channel layer have been presented as a solution to the demand for flexible, cheap, and transparent thin-film transistors (TFTs). In order to produce high-performance and long-sustainable portable devices with the solution-processed OS TFTs, the low-operational voltage driving current is a key issue. Experimentally, increasing the gate-insulator capacitances by high-k dielectrics in the OS TFTs has significantly improved the field-effect mobility of the OS TFTs. But, methodical examinations of how the field-effect mobility depends on gate capacitance have not been presented yet. Here, a systematic analysis of the field-effect mobility on the gate capacitances in the solution-processed OS TFTs is presented, where the multiple-trapping-and-release and hopping percolation mechanism are used to describe the electrical conductivity of the nanocrystalline and amorphous OSs, respectively. An intuitive single-piece expression showing how the field-effect mobility depends on gate capacitance is developed based on the aforementioned mechanisms. The field-effect mobility, depending on the gate capacitances, of the fabricated ZnO and ZnSnO TFTs clearly follows the theoretical prediction. In addition, the way in which the gate insulator properties (e.g., gate capacitance or dielectric constant) affect the field-effect mobility maximum in the nanocrystalline ZnO and amorphous ZnSnO TFTs are investigated.

Field effect devices

Abstract: 1. J-FET and MESFET. 2. MOS Fundamentals. 3. MOSFETs: An Introduction. 4. Nonideal MOS. 5. Modern FET Structures.

A brief analysis of the field effect diode and breakdown transistor

Abstract: The carrier densities of a field effect diode are calculated for the limit of a thin intrinsic silicon layer. The resulting current-voltage relation and the application of this device as a transistor are discussed. In forward bias, carrier densities can be modulated without the complications of the hot-electron effects present in regular field effect transistors. In reverse bias, it can be utilized as a transistor in which the breakdown voltage is modulated by the gate voltages.