Semiconductors transparent conducting oxides

Figure 9.7. Illustration of the usage of mesoporous films of transparent conducting oxides for novel types of solar cells. The dark gray areas correspond to ITO, the brighter ones to an oxide deposited onto the TCO matrix. The sphere symbolizes a dye. For instance, such films can be used as porous electrodes to include dyes and to deposit semiconductors such as ZnO. 

Fig. 1.19. Transparent conducting oxide electrodes in different types of thin film solar cells. TCO contacts are given at the bottom of each structure. The bottom most row indicates the doping type of the semiconductor, which is in contact to the TCO...

This process is obviously a natural scattering process in polycrystalline materials, since polycrystalline films exhibit a high concentration of crystallographic defects, especially dislocations [133,134]. However, this process is rarely used to explain experimental data of carrier transport in polycrystalline semiconductors and especially transparent conducting oxides [88], which is mainly due to the fact that in most works on transport properties of polycrystalline films the density of defects was not determined. Podor [135] investigated bended n-type Ge crystals with a dislocation density around 107 cm 2... 

ZnO and CdO are wide bandgap semiconductors, and these materials may serve as transparent conducting oxides for photovoltaics and flat panel displays. ZnO may also have applications in blue and ultraviolet fight emitting devices and laser diodes. Thin films of zinc and cadmium chalcogenides also have many potential applications. The technological goals of these materials have been smnmarized in several recent... 

The semiconductor nanoparticle most commonly used is the anatase form of Ti02 however, other mesoscopic oxides can also be used, such as Sn02, ZnO, Nb20s, WO3, and Ta20s. Dye molecules are chemisorbed onto the semiconductor (Fig. 6b), forming close to a monolayer. This dye-semiconductor assembly is arranged over a transparent conducting oxide and the set is put into contact... 

Minami, T. (2005) Transparent conducting oxide semiconductors for transparent electrodes. Semicond. Sci. Technol., 20, S35-S44,... 

Fig. 6.1 A design for a tandem photoelectrolysis system that uses nanostmctured semiconductor films of opposite cairier type that are deposited on opposite sides of a single substrate that is covered on both sides with a continuous transparent conducting oxide film. The larger bandgap material is transparent to the lower energy radiation that is absorbed by the smaller gap film on the backside of the substrate...

Fig. 9 Energy diagram showing the contact of the nanocrystalline semiconductor electrode with the transparent conducting oxide (TCO) substrate, and the change of Fermi levels and the vacuum level under illumination, with respect to the dark equilibrium. AE is the energy offset between the conduction band of the Xi02 and the transparent conducting oxide (TCO)...

The typical dye-sensitized solar cell contains broadly five components (1) a mechanical support coated with transparent conductive oxides (2) the semiconductor porous film composed of oxide, and the most widely researched material is Ti02 (3) a sensitizer adsorbed onto the surface of the semiconductor (4) an electrolyte containing a redox mediator and (5) a counter electrode capable of regenerating the redox mediator like platine [6-8]. 

ZnO, and heterostructure devices. Among the devices, light emitters, microcavities, optically pumped lasers, photodiodes, metal-insulator-semiconductor diodes, field-effect transistors, transparent conducting oxides, and transparent thin-fihn transistors based on ZnO, piezoelectric devices in the form of surface acoustic wave devices, and gas and biosensor followed by solar cells cap the discussion. 

Nanoparticles of Ti02 are deposited on to a glass support covered with a transparent conducting layer of tin-doped indium oxide (ITO). Each nanoparticle is coated with a monolayer of sensitising dye based on Ru(II). Photoexcitation of the dye results in the injection of an electron into the CB of the semiconductor. 

Transparent, conducting, tin oxide coatings are used in applications where light must pass through the substrate in order to strike the active element such as a photoconductive or photoelectric material. Chemically deposited films of silicon dioxide serve as masks on semiconductor materials for selective doping in the preparation of integrated circuits that can later be removed by chemical etching. 

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