Carrier Dynamics Investigated by Time-Resolved Optical Spectroscopy

Abstract

An optical investigation of the transport properties of carriers in a thick GaAs layer is presented. The electron transport is monitored by time‐resolved luminescence from the GaAs layer and an InGaAs quantum well beneath. The transients are mostly insensitive to the presence of external electric fields of both polarities, which indicates a carrier transport dominated by ambipolar diffusion. Spin measurements under a continuous‐wave low‐density regime show a strong conservation of the electron spin during the diffusion of electrons through the thick GaAs layer and their capture by the InGaAs well, but only for an applied field polarity that accelerates the electrons towards the well.

Ambipolar diffusion and spatial and time-resolved spectroscopies in semiconductor heterostructures

“…Electrons arriving at the interface of the QW proceed through it and recombine with holes generated by the p-doped InGaP barrier, which are accumulated in the QW, and the photoluminescence spectrum can thus be detected. 21 We proceed with the description of these processes, with the paper organized as follows: In Sec. II the basic theoretical aspects are described, while in Sec.…”