Semiconductor ionization potential

Figure 7.13. The definitions of ionization potential, Ie, work function, , Fermi level, EF, conduction level, Ec, valence level Ev, and x-potential Xe without (a) and with (b) band bending at the semiconductor-vacuum interface.

Brus, L. E. (1983). A simple model for ionization potential, electron affinity and aqueous redox potentials of small semiconductor crystallites. /. Chem. Phys., 79, 5566-5571. 

Bms LE (1983) A simple model for the ionization potential, electron affinity, and aqueous redox potentials of smaU semiconductor crystaUites. J Chem Phys 79 5566-5571... 

It should be mentioned that one can detect two types of equilibrium in the model of charge transfer in the absorbate - adsorbent system (i) complete transition of chemisorbed particles into the charged form and (ii) flattening of Fermi level of adsorbent and energy level of chemisorbed particles. The former type takes place in the case of substantially low concentration of adsorbed particles characterized by high affinity to electron compared to the work function of semiconductor (for acceptor adsorbates) or small value of ionization potential (for donor adsorbates). The latter type can take place for sufficiently large concentration of chemisorbed particles. 

Related Polymer Systems and Synthetic Methods. Figure 12A shows a hypothetical synthesis of poly (p-phenylene methide) (PPM) from polybenzyl by redox-induced elimination. In principle, it should be possible to accomplish this experimentally under similar chemical and electrochemical redox conditions as those used here for the related polythiophenes. The electronic properties of PPM have recently been theoretically calculated by Boudreaux et al (16), including bandgap (1.17 eV) bandwidth (0.44 eV) ionization potential (4.2 eV) electron affinity (3.03 eV) oxidation potential (-0.20 vs SCE) reduction potential (-1.37 eV vs SCE). PPM has recently been synthesized and doped to a semiconductor (24). 

As the size of a semiconductor crystal becomes small a regime is entered in which the electronic properties, e.g. ionization potential and electron affinity, are determined by size and shape of the crystals [113], When a quantum of light (hv) with energy exceeding the band gap falls on the surface of a semiconductor crystal there appears a bounded electron-hole pair known as an exciton... 

Dowden (27) in a theoretical approach similar to that used for metals, has examined the probability of positive ion formation on intrinsic and extrinsic semiconductors. The energy of activation of this process in intrinsic semiconductors is considered to be proportional to ) where / is the ionization potential of the activated complex (/ + Ab ) the activation energy decreases as (exit work function) increases and as AF decreases, — defining the Fermi level. In the case of n- and p-type semiconductors, the Fermi level will... 

Fig. 5.2. Energy diagram of a metal/semiconductor/metal Schottky barrier under open-circuit conditions, when the metals have different work functions. work function, Xs electron affinity, IP ionization potential, Eg energy gap, W depletion...

The ionization potential of D and the electron affinity of A may be modified by altering the mode of chemical substitution. In this manner it is possible to create molecules in which D and A are in the neutral ground state or in the charged state (as a result of the transfer of an electron from D to A). In principle, the former will behave like photoconductors or semiconductors, while the latter will behave like metallic conductors or superconductors, depending on the factors enumerated below. 

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