Semiconductor charge carrier mobility

Figure 2.9 Semiconductor charge carrier mobility and printing technique resolution requirements for printed electronics, (see Colour plates p. LII)...

One example of inorganic (particulate) materials is zinc oxide (ZnO). ZnO is a non-toxic and transparent material and a good n-type semiconductor. Charge carrier mobilities obtained in FETs exceed the amorphous silicon benchmark of 1 cm A s [24, 25]. However, to obtain these high field-effect mobilities, the ZnO films have to be annealed at temperatures incompatible with flexible substrates. 

Figure 17.1 Organic semiconductor charge carrier mobility requirements to allow fulfillment of the commercial roadmap for displays driven by organic TFTs...

It should also be briefly recalled that semiconductors can be added to nanocarbons in different ways, such as using sol-gel, hydrothermal, solvothermal and other methods (see Chapter 5). These procedures lead to different sizes and shapes in semiconductor particles resulting in different types of nanocarbon-semiconductor interactions which may significantly influence the electron-transfer charge carrier mobility, and interface states. The latter play a relevant role in introducing radiative paths (carrier-trapped-centers and electron-hole recombination centers), but also in strain-induced band gap modification [72]. These are aspects scarcely studied, particularly in relation to nanocarbon-semiconductor (Ti02) hybrids, but which are a critical element for their rational design. 

Klenkler RA, Xu G, Aziz H, Popovic ZD (2006) Charge-carrier mobility in an organic semiconductor thin film measured by photoinduced electroluminescence. Appl Phys Lett 88 242101... 

Unlike intrinsic semiconductors, in which the conductivity is dominated by the exponential temperature aud band-gap expression of Eq. (6.31), the conductivity of extrinsic semiconductors is governed by competing forces charge carrier density and charge carrier mobility. At low temperatures, the number of charge carriers initially... 

One of the fundamental criteria necessary for the applicability of a semiconductor model is the theoretical prediction of the temperature dependence of charge-carrier mobilities. The T n temperature dependence of... 

Stable polythiophene semiconductors 237 incorporating the thieno[2,3-fc]thiophene ring system were synthesized by Stille coupling of 5,5 -dibromo-4,4 -dialkyl-2,2 -bithiophene 235 with thieno[2,3-fc]thiophene-2,5-diylbis(trimethystannane) 236 (Scheme 48). The polymers 237 described showed both good charge carrier mobility and stability to ambient air and light [62],... 

The variability in the resistance-temperature characteristics at temperatures below about 800 °C can be attributed to impurities, the materials behaving as very complex, doped semiconductors (see Section 2.6.2 and Problem 2.10). The positive temperature coefficient of resistance observed at the higher temperatures suggests the effect of decreasing charge-carrier mobility with increasing temperature (see Section 2.6.2), but because of the complex nature of the materials both from the chemical and microstructural standpoints, this has to be regarded as speculation. 

The proportionality constant between the applied electric field and the resulting drift velocity is called the charge carrier mobility, jx. For electrons, = q r /ml ), for holes, ftp = 7(Trn/mj ). It should be noted that, owing to differences in the effective masses of electrons and holes, their mobilities within a semiconductor may be markedly different. The electrical conductivity, a, of a semiconductor is related to the free carrier concentrations by ... 

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