Ambipolar field

In this chapter we have reported on theoretical investigations of two different regimes of interaction between ultraintense EM radiation and plasmas, as examples of the application of the theoretical models developed in a previous chapter. First, we have studied the existence of localized spatial distributions of EM radiation, which appear in numerical simulations as a result of the injection of an ultrashort and intense laser pulse into an underdense plasma. Such solitonic structures originating from the equilibrium between the EM radiation pressure, the plasma pressure and the ambipolar field associated with the space charge have been described in the framework of both a relativistic kinetic model and a relativistic fluid approach. It has also been shown that... 

In the presence of the large fields present in the space-charge region, the collective coulombic interaction is overcome and there is a net separation of charge. In fact, the field magnitude is well in excess of the ambipolar fields and the carriers experience a large acceleration in the field region. 

Figure 17.4 Output and transfer characteristics of ambipolar field-effect transistors for a mixing ratio between Ceo and CuPc of 1 1 measured in the n-channel regime (a, c) as well as the p-channel regime (b, d). The substrate was 02-plasma treated and the film evaporated at 375 K substrate temperature. The direction of the hysteresis is indicated by arrows. (Figure adopted from Ref. [27].)...

Shkunov, M., Simms, R., Heeney, M., Tierney, S. and McCulloch, I., Ambipolar field-effect transistors based on solution-processable blends of thieno 2,3-b thiophene terthiophene polymer and methanofullerenes, Adv. Mater, 17, 2608, 2005. 

Anthopoulos, T.D., de Leeuw, D.M., Cantatore, E., Setayesh, S., Meijer, E.J., Tanase, C., Hummelen, J.C. and Blom, P.W.M., Organic complementary-hke inverters employing methanofullerene-based ambipolar field-effect transistors, Appl. Phys. Lett., 85, 4205 207, 2004. 

Yamamoto, T. et al., Ambipolar field-effect transistor (FET) and redox characteristics... 

The group of Meijer and Schenning has constructed ambipolar field-efifect transistors from imides-diaminotriazines H-bonded p-n dyad complexes 29 based on OPV4T in combination with PBI-2 [89]. The transistors show two independent pathways for charge transport. In contrast, processing of OPV and PBl that are not connected by H-bonds formed charge transfer donor-acceptor complexes. They showed no mobility in field-effect transistors, presumably due to an unfavorable supramolecular organization. 

T. Lei, J.-H. Dou, X.-Y. Cao, J.-Y. Wang, J. Pei, A BDOPV-Based Donor-Acceptor Polymer for High-Performance N-Type and Oxygen-Doped Ambipolar Field-Effect Transistors. Adv. Mater. 2013,25, 6589-6593. 

T. Lei, J.-H. Dou, Z.-J. Ma, C.-J. Liu, and J. Pei, Chlorination as a Usefid Method to Modulate Conjugated Polymers Balanced and Ambient-Stable Ambipolar Field-Effect Transistors and Inverters Based on Chlorinated Isoindigo Polymers , Chem. Sci. 2013, 4, 2447. 

Lei T, Dou JH, Cao XY, Wang JY, Pei J (2013) A BDOPV-based donor-acceptor polymer for high-performance n-type and oxygen-doped ambipolar field-effect transistors. Adv Mater 25 6589-6593... 

Figure 6.88. Band structure and the ambipolar field effect in graphene. Conduction and valence bands meet at the Dirac point without an external field in the presence of a gate bias, the Fermi level moves above/below the Dirac point to generate free carriers. Reproduced with permission from Nature Mater. 2007, 6, 183. Copyright 2007 Nature Publishing Group.

Anthopoulos TO, de Leeuw DM, Cantatore E, Setayesh S, Meijer EJ, Tanase C, Hummelen JC, Blom PWM (2004) Organic complementary-like inverters employing methanofullerene-based ambipolar field-effect transistors. Appl Phys Lett 85 4205-4207... 

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