Intraband absorption and interband photoconductivity transients in Ge/Si quantum dots

Abstract

In this work a series of relaxation curves of photoinduced intraband absorption and interband photoconductivity were measured in Ge/Si quantum dots in the temperature range from 80 K to 300 K and at different levels of the interband excitation. The low-temperature experimental curves show a two-step decay of a population of quantum dots. At high temperatures there is only one decay component. A simultaneous analysis of photoinduced intraband absorption and interband photoconductivity relaxation curves shows that quantum dots act as traps for non-equilibrium holes only at low temperatures.