Kinetics of Excess Carrier Distribution in Bilateral Macroporous Silicon with Different Thickness of Porous Layers

The kinetics of the concentration distribution of excess minority charge carriers in bilateral macroporous silicon with different thicknesses of porous layers is presented. The dependence of the duration of the non-exponential beginning of relaxation of the distribution of the concentration of excess charge carriers in bilateral macroporous silicon on the thickness of the frontal macroporous layer is revealed. A similar dependence is observed in the rear macroporous layer 200 m thick after the termination of the generation of excess charge carriers by light with a wavelength of 1.05 m. The concentration of excess charge carriers in the frontal macroporous layer rapidly decreases due to the high generation and recombination of excess charge carriers. The decrease in the excess minority carrier concentration in the rear macroporous layer 100 m thick and the monocrystalline substrate has a very short non-exponential part due to the low generation and recombination of excess minority charge carriers, respectively. The diffusion equation written for bilateral macroporous silicon is solved by a numerical method. The boundary and initial conditions are used for the solution. The boundary condition is written at the boundaries of macroporous layers. The initial distribution of the excess minority carrier concentration in bilateral macroporous silicon in the direction parallel to the pores is found from a system of equations. This initial distribution is calculated under the condition that macroporous silicon is illuminated with light with a wavelength of 0.95 m or 1.05 m. In the initial distribution of the excess minority carrier concentration, one or two maxima are observed. Two maxima are observed when bilateral macroporous silicon is illuminated with light at a wavelength of 0.95 m.