Abstract

The rapid development of femtosecond light sources extending to the mid-infrared spectral range [1] allows the direct selective observation of electron or hole dynamics in bulk or low- dimensional semiconductor structures. In this paper, we study the inter- and intra-subband relaxation of electrons in n-type modulation- doped GaInAs/AlInAs multi-quantum wells (MQWs) which provides new information on the n=2 lifetime and on electron thermalization. The sample consists of 50 GalnAs QW's of 8 nm width separated by 14 nm thick AlInAs barriers the centre of which is delta-doped with Si atoms. The pump-probe scheme of our time-resolved experiments is explained in the insert of Fig. 1.

© 1996 Optical Society of America