Excess carrier concentration

Fig. 15. Excess carrier concentration in HgCdTe in a saturated Hg vapor as a function of temperature where the dashed line represents Hg vacancies. The extrinsic impurity concentration can be adjusted in the growth process from low 10 up to mid-10. Low temperature annealing reduces Hg vacancy...

A method for quantification of the CL, the so-called MAS corrections, in analogy with the ZAP correction method for X rays (see the article on EPMA), has been proposed to account for the effects of the excess carrier concentration, absorption and surface recombination. In addition, a total internal reflection correction should also be included in the analysis, which leads to the MARS set of corrections. This method can be used for further quantification efforts that also should involve Monte Carlo calculations of the generation of excess carriers. 

In the expression for the excess carrier concentration at the boundary to the space charge layer, Ap(W), the recombination velocity at the back contact, S,b, is contained (see equations A8, A9 in [45].). The terms C, C, D, D and the prefactor A contain expressions that are independent of the variable x. They are given in Appendix 2.A. Figure 2.4 shows examples of excess minority carrier profiles for a back contact recombination velocity Srb of 10 cm s which is in the range of the thermal velocity [46] for a set of minority carrier diffusion lengths that range from poor bulk mate-... 

Figure 2.5 Charge collection efficiency Qc as a function of the minority carrier diffusion length for three excess carrier concentrations at the space charge layer boundary full line,...

Figure 2.6 Spatial dependence of excess carrier concentration Ap(x) for different diffusion voltages in the space charge region and for low excess carrier consumption at the surface (x = 0), expressed by...

In the low injection limit, APmw is given by a sensitivity factor S, the electrical field of the microwaves, the mobihties of holes and electrons, and the respective excess carrier concentrations. For the one-dimensional case (see Figures 2.3 and 2.4), the excess microwave signal is given by... 

Large excess carrier concentrations produced either by high fields or photon excitation are associated with an even larger non-equilibrium density of trapped electrons and holes. These in turn will modify the spatial potential fluctuations which determine the energy distribution of loc ized states and the position of the percolation thresholds. A self-consistent treatment of the electron states for different occupation functions has not yet been carried out. 

This technique affords a simple and fast separation method with exceptionally high mutual decontamination factors. The time for separation la less than 15 minutes. Improper paper purification. Impure reagents, or excess carrier concentration may cause poor separations. 

In a model that considers the situation at the semiconductor-electrolyte contact, the charge transfer rate and the surface recombination velocity have to be included [59]. In such a model, the currents related to charge transfer and to surface recombination are expressed by the excess carrier concentration at the surface (x = 0) according to... 

The excess minority carrier concentration can be viewed as an additional stationary concentration term that enters the chemical potential although this terminology is strictly only valid in equilibrium. Extending the consideration to a stationary illumination situation where an excess carrier concentration profile exists for a given minority carrier lifetime and for defined boundary conditions, the concept of quasi-Fermi levels can be introduced. Using the Boltzmann... 

Figure 3.5 shows the distribution of excess carrier concentration near to barrier and antibarrier junctions of the semiconductor-semiconductor and metal-semiconductor type. 

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