Dimensionless solution of the equation describing the effect of surface recombination on carrier decay in semiconductors

Abstract

A dimensionless solution is presented for the surface recombination component τs of the effective lifetime τeff of the fundamental mode of excess carrier decay in semiconductors. The case of different surface recombination velocities S1 and S2 is analyzed. As the problem is solved in terms of dimensionless variables, the solution obtained is a general one. A normalized surface lifetime τ *s is plotted as a function of normalized surface recombination velocities S*1 and S*2. This allows rapid calculation and visualization of the influence of surface recombination on τs, for all possible cases of recombination parameters. That is, for any value of S1, S2, W (the width of a sample), and D (the diffusion constant) a solution for the surface lifetime τs can be found from the one graphical solution. It is a useful tool for rapidly interpreting the effect of surface recombination in transient lifetime measurement experiments. For the cases where S=S1=S2, or where S1 or S2 is zero, this approach is an elegant tool for investigating useful approximations for τs.