The role of traps with arbitrary distribution in photoinduced charge carrier dynamics in semiconductor quantum dots

Abstract

The presented model shows that for any trap distribution in semiconductor quantum dots (QDs) the evolution of photoinduced charge carriers (as a rule, responsible for observed signals in optical spectroscopic studies of QDs) consists of two prominent components. The fast component lying in the picosecond range reflects the increase and the fast decay of the charge carrier population, and the slow one exhibits the profile of a long-time mono-exponential decay with a decay time ranging from tens ns to few µs. It is important, that the decay time of the slow component depends not only on relaxation processes in QDs but also on a profile of a trap distribution. This finding opens up promising possibilities to gain a new insight into the role of traps in QDs photophysical characteristics by carrying out a detailed analysis of the long-time mono-exponential decay of experimental signals associated with the charge carrier population.