High resolution density of states spectroscopy in semiconductors by exact post-transit current analysis

We show that the analysis of post-transit photocurrent i(t) to determine the energy distribution g(E) of trapping states in a semiconductor is capable of much finer energy resolution than has hitherto been realized. Existing methods use a Laplace inversion of i(t) data to find g(E) but employ a delta function approximation for trap release times. In this article we retain the exponential distribution function for the release time and solve the rate equations directly. The analysis is performed on computer generated post-transit data for distributed and discrete traps, and compared with the earlier method and other related transform methods for determining the density of states, g(E). © 2000 American Institute of Physics.