Temperature depopulation of the GeSi/Si quantum dots with non-equilibrium charge carriers

Abstract

We study the temperature dependencies of equilibrium and photo-induced infrared absorption in GeSi/Si quantum dots in a wide spectral range. We show that, in spite of the large valence band offset at GeSi/Si interface and strong confinement for holes, the effect of intensive temperature depopulation of the GeSi/Si quantum dots can take place even at the temperatures below 300 K due to the large difference in density of states of the silicon valence band and quantum dot states, when the bipolar diffusion of charge carriers is not restricted.