Optical and Transport Properties of Excitons in Cu2O

摘要

We present data on various aspects of excitons in Cu2O. From a series of all optical,spatially and temporally resolved transport measurements we deduce a rather small Augercoefficient in the range 10-24-10-23cm3/ns. Additionally we get values for the lifetimeof the 1s paraexciton of the yellow series up to 3ms and diffusion constants of theorder of 10cm2/s. In another experiment we measured the temperature dependent totalexternal luminescence quantum efficiency with values around 0.005%. Measurements of theinterexcitonic transitions with a visible pump and a probe in the infrared show two distinct,hitherto unknown lines at 113 and 117 meV the origin of which is discussed in terms of the1s to 2p transitions. A lineshape analysis suggests a new value for the 1s effective mass withmLs ≈2m0. Furthermore we will evaluate a probable saturation behaviour of the Cu2O/CuSchottky barrier exciton detector (see e.g. [1, 2, 3, 4]) and give some comments about possibleBose-Einstein condensation of the 1s excitons.