Fermi energy pinning

Singh P, Singh R, Gale R, Rajeshwar K, DuBow J (1980) Surface charge and specific ion adsorption effects in photoelectrochemical devices. J Appl Phys 51 6286-6291 Bard AJ, Bocarsly AB, Pan ERF, Walton EG, Wrighton MS (1980) The concept of Fermi level pinning at semiconductor/liquid junctions. Consequences for energy conversion efficiency and selection of useful solution redox couples in solar devices. J Am Chem Soc 102 3671-3677... 

Manipulating surface states of semiconductors for energy conversion applications is one problem area common to electronic devices as well. The problem of Fermi level pinning by surface states with GaAs, for example, raises difficulties in the development of field effect transistors that depend on the... 

Negative U defects pin the Fermi energy. Since the upper le level is empty, and the lower 2e level is filled, must obviously lie between these two energy levels. The pinning of the Fermi energy position is demonstrated by assuming that the AT defects contain a variable density of electrons, n, where 0 < < IN. The law of mass action (see Section... 

Under conditions of charge neutrality, n = N, the Fermi energy is midway between the le and 2e states and as n varies it departs very little from this position. For example, when = O.IA, the shift is less than 2kT, so that the Fermi energy is strongly pinned. In contrast, when the defect has a positive 7, the Fermi energy moves rapidly from the lower le level to the upper 2e level near n = N. The different behavior of E-g is shown in Fig. 4.5. 

Several consequences follow from the analogy with chalcogenide glasses. Valence alternation pairs pin the Fermi energy (see Section... 

Conductivity data for n-type and p-type samples above the equilibration temperature are shown in Fig. 7.4 and similar data are in Fig. 5.2. The conductivity is activated with a prefactor of 100-200 cm for both doping types and the activation energy is 0.3-0.4 eV in n-type material and 0.4-0.6 eV in p-type. In the thermal equilibrium regime, the Fermi energy is pinned by the defect and dopant states and consequently the statistical shift is small, as is discussed in Section 6.2.2. Yp may be calculated from a numerical... 

In some ways, however, semiconducting polymers are more robust than their inorganic counterparts. In particular, whereas pinning of the Fermi energy by surface states is a major problem in conventional semiconductors, the Fermi... 

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