Bulk generation

The maximum value of the minority-carrier current, which may flow under steady state conditions from the semiconductor bulk to the surface, is called the limiting current. It is determined by bulk generation of electron-hole pairs. As simple calculation shows (see, for example, Myamlin and Pleskov, 1967), the absolute value of the limiting current of minority carriers, holes for illustration, is... 

The exciton migration within aggregates of cyanine dyes and the possibility of oxygen diffusion into the porous dye film result in a bulk generation of photocurrent [80]. Photoholes produced due to the oxidation of excitons by molecular oxygen diffuse to the back contact. The diffusion coefficient of charge carriers in dye layer (Dc) can be evaluated from the potential-step chronoamperometric measurements in the indifferent electrolyte. Considering dye film as a thin-layer cell, the current vs. time dependence can be described as follows [81] ... 

Since the probability of the initial recombination can be expressed by the separation step rates, the natural way of its determination is to measure the bulk-generated photocurrent. However, one should keep in mind that the measured photocurrent contains carrier mobilities in addition to the effective separation probability (f/oG). The carrier mobilities... 

Physically, eqn. (220) has the following significance. The first term in the numerator is the depletion layer generating term and the second the bulk generating term. In the denominator, the first term is the interfacial faradaic term and the second a transport term across the depletion layer. There are a number of important specific cases that can be extracted from the formula. If we have a narrow bandgap material, then bulk generation will tend to dominate and we have... 

The slope of a Zerbst Plot is given by determine the generation lifetime. We like to point out that the mtercept should not be interpreted as the surface generation velocity as is sometimes done. The intercept is a complicated function of surface generation, quasi-neutral bulk generation and it also depends on the assumptions used in the Zerbst analysis. [90] To extract a surface generation velocity from the intercept is very misleading. 

Figure 19. Restricted partition functions for the rth order 5-simplex. Here and represent the bulk generating functions for the polymer chain and S and...

Any intrinsic property that influences the conductivity of an electrodematerials system, or an external stimulus, can be studied by IS. The parameters derived from an IS spectrum fall generally into two categories (a) those pertinent only to the material itself, such as conductivity, dielectric constant, mobilities of charges, equilibrium concentrations of the charged species, and bulk generation-recombination rates and (b) those pertinent to an electrode-material interface, such as adsorption-reaction rate constants, capacitance of the interface region, and diffusion coefficient of neutral species in the electrode itself. 

The further text shortly considers all of the three main bulk generation-recombination mechanisms in direct narrow-bandgap semiconductors. A unilied g-r term is presented to be utilized in modeling and optimization of photonic IR detectors. In addition to that, some useful approximations are given that may significantly speed up and simplify modeling. 

When the jump is made from P/pVtank to s, an assumption that the turbulence is homogeneous is implied. This assumption is clearly a poor one in a stirred tank, where the levels of turbulence can vary by a factor of 100 from the impeller to the bulk. Generation and dissipation are vastly different between the impeller region and the regions away from the impeller. For shear-sensitive materials such as cells, their survival depends more on the maximum shear they see than on the average. In such cases, using P/pVtank as some kind of an average dissipation is... 

Wind movements in the atmospheric BL directly impact water turbulence and currents in the surface layers. However, the role of wind in generating turbulence and currents in the bottom-water (i.e., hypolimnion) above the sediment bed is the issue of interest here. Wind stress on the surface moves water masses in bulk generating internal water movements that are transmitted deep into the water column resulting in bottom currents. However, these are also sporadic in direction, magnitude, and duration. 

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