Heterojunction field-effect transistors

Keller, S., Wu, Y. E, Parish, G., Ziang, N. Q., Xn, J. J., Keller, B. R, DenBaars, S. P. and Mishra, U. K. (2001) GaUium nitride based high power heterojunction field effect transistors Process development and present status at UCSB , IEEE Transactions on Electron Devices, 48(3), 552-559. 

Contacts are the elementary building blocks for all electronic devices. These include interfaces between semiconductors of different doping type (homojunctions) or of different composition (heterojunctions), and junctions between a metal and a semiconductor, which can be either rectifying (Schotlky junction) or ohmic. Because of their primary importance, the physics of semiconductor junctions is largely dealt with in numerous textbooks [11, 12]. We shall concentrate here on basic aspects of the metal-semiconductor (MS) and, above all, metal-insulator-semiconductor (MIS) junctions, which arc involved in the oiganic field-effect transistors. 

See also Field effect transistors (FETs) Heterojunction insulated gate FETs (HIGFETs), 22 164. See also Field effect transistors (FETs) Heterojunction photodiode arrays,... 

Field-effect transistors (FETs) Heterojunction bipolar transistors (HBTs) High electron mobility transistors (HEMTs) Metal oxide semiconductor FETs (MOSFETs) Single-electron transistors (SETs) Single-heterojunction HBTs (SH-HBTs) Thin-film transistors (TFTs) hydrogenated amorphous silicon in, 22 135... 

The incorporation of siloles in polymers is of interest and importance in chemistry and functionalities. Some optoelectronic properties, impossible to obtain in silole small molecules, may be realized with silole-containing polymers (SCPs). The first synthesis of SCPs was reported in 1992.21 Since then, different types of SCPs, such as main chain type 7r-conjugated SCPs catenated through the aromatic carbon of a silole, main chain type cr-conjugated SCPs catenated through the silicon atom of a silole, SCPs with silole pendants, and hyperbranched or dendritic SCPs (Fig. 2), have been synthesized.10 In this chapter, the functionalities of SCPs, such as band gap, photoluminescence, electroluminescence, bulk-heterojunction solar cells, field effect transistors, aggregation-induced emission, chemosensors, conductivity, and optical limiting, are summarized. 

Also organic compound like metal phthalocya-nines [xxvi] and electronic conducting polymers [xxvii] are used as gas-sensitive layers in resistive sensors, POSFETs (polymer oxide silicon field-effect transistors), heterojunction diodes (e.g., polyrrole on... 

Jenekhe, Watson, and coworkers [277] reported synthesizing three new donor-acceptor conjugated polymers incorporating thieno[3,4-c]pyrrole-4,6-dione acceptor and dialkoxybithiophene or cyclopentadithiophene donor units. The thieno[3,4-c]pyrrole-4,6-dione acceptor containing materials were studied in bulk heterojunction solar cells and organic field-effect transistors. The polymers had... 

FigurelS.lO (a) Molecular structures of the n- (b) Schematics of bipolar field-effect transistors channel (BBL) and p-channel polymer based on n/p polymer heterojunctions, (c)...

A film of electroactive polymer [Os(bpy)2(vpy)2p, sandwiched between Pt and Au electrodes, becomes conductive when both the electrode potentials have appropriate values such that the mixed valent state, Os(III)/(II), is generated. Such arrangements are used in two-terminal and three-terminal diodes Solid-state organic heterojunctions utilizing two conducting polymers [PA and poly(A-methylpyrrole) junctions] were reported The electronic properties can be modified chemically. A field-effect transistor was fabricated utilizing chemically prepared poly(A-methyl-pyrrole)... 

Specific device configurations in which curtailment of misfit dislocation formation enhances performance are the heterojunction bipolar transistor and the modulation doped field effect transistor. In order to suppress misfit dislocation for-... 

Wtmg J, Wang HB, Yan XJ, Huang HC, Yan DH (2005) Oiganic heterojunction and its application for double channel field-effect transistors. Appl Phys Lett 87 093507... 

Heterojunction diodes can behave as homojunction diodes or Schottky barriers. They are used, for example, to control direction of carrier injection, induce electron or hole gas layers, and control energy gap on one side of the jrmction. Bipolar junction transistors consist of three layers of semiconductor with alternating doping type where the center layer of the three is relatively thin. The three layers are, respectively, the emitter, base, and collector. A small current emitter to base allows a large current emitter to collector when properly biased. Field-effect transistors have three regions, source, channel, and drain as well as a gate, which controls the conductivity of the channel connecting source to drain. 

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