Experimental evidences of carrier distribution and behavior in frequency in a BMFET modulator

We propose a novel method to monitor the carrier plasma distribution in a bipolar mode field effect transistor light modulator, using standard emission microscopy. Our bi-dimensional maps validate the theoretical predictions of plasma distribution as a function of the device bias. Dynamical measurements provide an experimental evidence of a frequency threshold in the electric field induced plasma distribution. Below 500 kHz generation/recombination processes while above drift phenomena allow the plasma localization in the device. An effective carrier lifetime >= 2 mu s was extrapolated.