Photoconductivity Kinetics in Bilateral Macroporous Silicon

The photoconductivity kinetics in bilateral macroporous silicon as a function of the pore depth of each macroporous layer is calculated by the finite-difference method. Steady-state photoconductivity in bilateral macroporous silicon is found using a system of equations. We use the excess minority carrier's diffusion equation, initial and boundary conditions to calculate the photoconductivity kinetics. Steady-state photoconductivity excited by light with a wavelength of 0.95 m and 1.05 m is used as the initial condition. We take into account that light passes through the frontal and rear macroporous layers, propagating through the silicon matrix and pores. The boundary condition is written at the boundaries of each macroporous layer. The kinetics of photoconductivity in bilateral macroporous silicon 500 m thick is calculated under the condition that the pore depth of one macroporous layer is 100 m, and the pore depth of another layer of macroporous silicon varies from 0 to 400 m. It is shown that the initial photoconductivity decay period increases as the depth of each macroporous silicon layer increases. On a semi-logarithmic scale, the photoconductivity decay, which is described by an exponential law, changes its slope when the pore depth of the frontal or rear layer of macroporous silicon is more than 250 m or 200 m, respectively. The exponential part of the photoconductivity changes its slope no matter what wavelength of 0.95 m or 1.05 m excited stationary photoconductivity. The dependence of the photoconductivity kinetics on the pore depth of the frontal and rear layers of macroporous silicon is almost identical when the photoconductivity is excited by light with a wavelength of 1.05 m. The photoconductivity decay in macroporous silicon with through pores is described by an exponential law.