P-type metal-oxide semiconductors

The source and drain are both p-type if the current flowing is holes. Surface field effect transistors have become the dominant type of transistor used in integrated circuits, which can contain up to one billion transistors plus resistors, capacitors, and the very thinnest of deposited connection wires made from aluminum, copper, or gold. The field effect transistors are simpler to produce than junction transistors and have many fevorable electrical characteristics. The names of various field effect transistors go by the abbreviations MOS (metal-oxide semiconductor), PMOS (p-type metal-oxide semiconductor), NMOS (n-type metal-oxide semiconductor), CMOS (complementary metal-oxide semiconductor—uses both p-type unipolar and n-type unipolar). 

Cuprous oxide (CU2O) is a p-type metal oxide semiconductor with the band gap between 2.0 and 2.2 eV [20]. The small band gap energy is beneficial for reduction and oxidation of water under visible light irradiation. Also, its lattice structure is mainly made up of the chains of linear bonds (-0-Cu -0-). Therefore, the material... 

Figure 4.12. Charge distributions Qeft) and band diagrams (right) for an n-type metal-oxide-semiconductor (nMOS) capacitor, with different gate bias modes. Shown are (a) Kgate = t -p-Q, (b) accumulation (Kgate < (c) depletion (KpB < fgate < hr), and (d) inversion (Vj < Kgate)- and Vp-Q...

In order to have more infoimation on the nature of the oxygen species active in partial and total oxidation we investigated the interaction of the hydrocarbons with the pre-oxidized surfaces of oxides where different types of surface oxygen species are formed. In particular we investigated p-type semiconductors like chromia, chromites and cobalt oxide C03O4. Moreover, we studied n-type metal oxides like FezOs, metal ferrites and CuObased catalysts. 

The rapid developments in the microelectronics industry over the last three decades have motivated extensive studies in thin-film semiconductor materials and their implementation in electronic and optoelectronic devices. Semiconductor devices are made by depositing thin single-crystal layers of semiconductor material on the surface of single-crystal substrates. For instance, a common method of manufacturing an MOS (metal-oxide semiconductor) transistor involves the steps of forming a silicon nitride film on a central portion of a P-type silicon substrate. When the film and substrate lattice parameters differ by more than a trivial amount (1 to 2%), the mismatch can be accommodated by elastic strain in the layer as it grows. This is the basis of strained layer heteroepitaxy. 

Metal sulfides play an important role in catalyzing a wide variety of hydrogenations (e.g., of fats, coal, or olefins) and also desulfurization reactions, which are used in pretreatment of fossil fuels to reduce the emission of sulfur oxides during combustion (Section 8.5). Molybdenum disulfide, an important defect catalyst, can be made to function as an n-type (Moi+xS2) or p-type (Mo1 xS2) semiconductor by exposure to an appropriate mixture of H2S and hydrogen at temperatures on the order of 600 °C. The equilibrium... 

MOSFETs. The metal-oxide-semiconductor field effect transistor (MOSFET or MOS transistor) (8) is the most important device for very-large-scale integrated circuits, and it is used extensively in memories and microprocessors. MOSFETs consume little power and can be scaled down readily. The process technology for MOSFETs is typically less complex than that for bipolar devices. Figure 12 shows a three-dimensional view of an n-channel MOS (NMOS) transistor and a schematic cross section. The device can be viewed as two p-n junctions separated by a MOS capacitor that consists of a p-type semiconductor with an oxide film and a metal film on top of the oxide. 

Metal-oxide-semiconductor FETs (MOSFETs) were also prepared by electrochemical polymerization using PPy and N-alkyl substituted PPy films, including poly (N-methylpyrrole) (PNMePy) and poly (N-ethylpyrrole) (PNEtPy) as a p-type semiconductor and p-toluenesulfonic acid monohydrate as a supporting electrolyte [168]. Figure 8.93 represents the cross-sectional view of the fabricated MOSFET. The mobility of PPy and PNEtPy FETs was 1.7 cm s, which is close to the value of silicon inorganic transistors [168]. 

Both the light-emitting diode (LED) and the FET structures can be found in classic textbooks discussing semiconductor devices [29]. The device structures commonly used are those of the P-N (or P-i-N) diode for the LEDs and the lateral metal oxide semiconductor (MOS) FET. These structures are based on (currently standard) processes of multilayer deposition as well as selective N and P type doping (see Figure 7.1) and rely on the mobility of 1 cm v s or more. 

Organic semiconductors are used in many active devices. Many can be processed in solution and can therefore be printed. The charge transport properties largely depend on the deposition conditions, which are influenced by the nse of solvents, the deposition technique, concentration, interfaces and so on. Most of the organic semiconductors used today are p-type (e.g., pentacene and polythiophene), but the first n-type materials have also become available and these mean that complementary metal-oxide-semiconductor (CMOS) circuits can now be fabricated. 

Epitaphial effects of a scale can influence diffusivity as does any defect such as porosity, grain boundaries, cracks, dislocation substructures, etc. Impurity cations can have a great effect on diffusivity in the oxide depending on the valence of the impurity ion and the semiconducting properties of the scale. Common scales formed from oxides, sulfides, and nitrides can be classified as p-type, n-type, or amphoteric semiconductors. The p-type, metal-deficit scales are nonstoichiometric with cation vacancies present. Impurity ions with valencies greater than the p-type semiconductor will tend to increase the concentration of cation vacancies and, hence, diffusivity. Lower vacancy ions will have the opposite effect. Impurity ions with the same valence should have little effect on diffusion. The n-type semiconductors... 

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