Electron trap shallow

Sulfur sensitization increases both the depth of shallow electron traps and the stabilization energy of the silver-atom center. These changes are sufficient to account for the overall increase in sensitivity" and its subsequent decrease at concentrations above the optimum. The population of free electrons is so reduced that recombination is now largely between free holes and trapped electrons. 

Electron hole pairs generated by photon absorption enable oxygen to desorb from the surface (bottom of Fig. 3). The oxygen desorption annihilates some of the holes, thereby decreasing the surface, so that electrons are now able to move from one ZnO grain to another. Thus, photoconductivity of the layer is produced. In the dark period which follows, the photoconductivity of the layer is preserved for some time due to the large number of shallow electron traps. 

A number of important points arise from these plots. The first is that the observed photocurrent of the repeated study increases with applied potential at a faster rate than the associated dark current. This may be attributed to the electrons being transferred from the conduction band or one type of shallow electron trap at or near the particle surface (typical electron trapping times are <100fs for CdS, see Section 9.2.1 above) [96-... 

Shallow electron traps None Morphological sites with positive electron affinity (inverse kink, etc.)... 

Shallow electron traps MgOcorner(6 ) Trapped electrons at exposed cations... 

Shallow electron traps (Sect. 2.3.10). Some specific sites at the MgO surface exhibit electron affinities of about 1 eV and can bind electrons. Among these sites, there are low-coordinated cations, like an Mg 3g corner site, divacancies, and other morphological sites like the reverse corner. 

After relaxation to the Is ground state, the electron may still be thermalized. If this process is dominant, as it is for Pb2+ and Cd2+, the impurity then behaves as a shallow electron trap affecting both the rate at which electrons are made available for latent image formation and their location in the silver halide lattice. 

It should be noted that there is one mutual TL glow peak at 60 K in all curves (see Figure 9.13, curves 1-3). It allows concluding that there are additional shallow electron traps, providing electrons through the conduction band to all types of acceptor centers during thermal stimulation, as it happens in the delocalized recombination process. That means that in AIN ceramics we observe coexistence of delocalized and localized recombination types. 

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