Acceptors thermal activation energy

The literature abounds with reports of thermal activation energies for shallow donors in GaN, obtained from Hall effect measurements over a range of temperatures, above and below room temperature, though their interpretation is rendered problematic by a number of complicating factors. At low temperatures there is clear evidence for impurity band conduction (see, for example, [31]) which severely limits the temperature range over which data may usefully be fitted to the standard equation for free carrier density n in terms of the donor density ND and compensating acceptor density NA ... 

The measurement of a thermal activation energy implies that type conversion has been achieved, which restricts application to a very few acceptors, i.e. Mg, Ca, Be and an unknown native defect (possibly V<3a). Mg is the only acceptor which has been at all widely studied, mainly in GaN but also, to some... 

An additional argument is derived from the comparison of the energy of the absorption edge and the. thermal activation energy of conductivity in acceptor... 

In this study we examined the conductivity relationships and thermal activation energies of several novel phenothiazines and metallotetra-benzporphyrins complexed with common electron acceptors. We also studied ternary complexes of these compounds with polyvinylpyridine. 

The rate of a given reaction depends on the thermal activation conditions of the particle in donor and acceptor, factors which are accounted for in the Marcus model [6,7] or models where the vibrational wave functions are included [8-10], The reaction rate is derived in rather much the same way as for ordinary chemical reactions, using the concept of potential energy surfaces (PES s) [6]. The electronic factor is introduced either as a matrix element H]2 or as an... 

Electron transfer reactions and spectroscopic charge-transfer transitions have been extensively studied, and it has been shown that both processes can be described with a similar theoretical formalism. The activation energy of the thermal process and the transition energy of the optical process are each determined by two factors one due to the difference in electron affinity of the donor and acceptor sites, and the other arising from the fact that the electronically excited state is a nonequilibrium state with respect to atomic motion (P ranck Condon principle). Theories of electron transfer have been concerned with predicting the magnitude of the Franck-Condon barrier but, in the field of thermal electron transfer kinetics, direct comparisons between theory and experimental data have been possible only to a limited extent. One difficulty is that in kinetic studies it is generally difficult to separate the electron transfer process from the complex formation... 

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