Experimental investigation of the electron-hole plasma expansion in CdS

Using a two beam method for gain and reflection spectroscopy, we introduce a new technique allowing for a spatial and temporal resolution of 5 μm and 2 nsec, respectively. With this method we are able to investigate the optical gain, the reflection and the spatial extension of an electron-hole plasma under stationary excitation conditions. The experiments are performed with the II–VI compound semiconductor CdS. Our results are compared with those from other authors who deduced the electron-hole plasma properties mainly from luminescence experiments.