Semiconducting charge transport

Semiconducting Ceramics. Most oxide semiconductors are either doped to create extrinsic defects or annealed under conditions in which they become non stoichiometric. Although the resulting defects have been carefully studied in many oxides, the precise nature of the conduction is not well understood. Mobihty values associated with the various charge transport mechanisms are often low and difficult to measure. In consequence, reported conductivities are often at variance because the effects of variable impurities and past thermal history may overwhelm the dopant effects. 

Fig. 16.7 Energy-band diagrams of DSSCs with incorporated (a) semiconducting (s-) SWCNTs and (b) metallic (m-) SWCNTs. The solid and dashed arrows represent desired charge transport and undesired recombination processes. Adapted from Guai etal. [95].

Zhang Y, de Boer B, Blom PWM (2009) Controllable molecular doping and charge transport in solution-processed polymer semiconducting layers. Adv Funct Mater 19 1901... 

Poly(3,3 -dialkyl-2,2 5 2-terthiophene) derivatives, (11), prepared by McCulloch [3] were also effective in electronic components as charge transport materials and semiconducters. 

Comil, J. et ah, Charge transport versus optical properties in semiconducting crystalline... 

Self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures in which ordered microcrystaUine domains are embedded in an amorphous matrix [20,21]. This has important consequences for electrical properties of these materials Charge transport is usually limited by the most difficult hopping processes and is therefore dominated by the disordered matrix, resulting in low charge-carrier mobilities (<10 cm V s ) [22]. 

Topinka, M. A., Rowell, M. W., Goldhaber-Gordon, D., McGehee, M. D., Hecht, D. S. and Gruner, G. (2009), Charge transport in interpenetrating networks of semiconducting and metallic carbon nanotubes . Nano Letters, 9,1866-71. 

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