Abstract

We undertook a systematic degenerate-four- wave-mixing (DFWM) study of the coherent exciton dynamics in a series of CdTe/CdZnTe single quantum wells (QWs), with the QW thickness varying between 18 and 130 Å. The enhanced excitonic character and the shallow potential barriers (80 meV for the electrons and 25 meV for the heavy holes) are the two main features that distinguish this QW system from the intensely studied GaAs/AlGaAs one.¹ The low-temperature inhomogeneous exciton linewidths range between 1.3 and 2 meV, and the corresponding Stokes shift ranges between 0.5 and 1 meV, depending on the QW thickness. It is important to note that the exciton linewidth decreases for the narrower QWs. This behavior is contrary to expectations and is opposite to that observed for GaAs/AlGaAs systems. The DFWM measurements were two-pulse experiments, using 0.8-ps Ti:sapphire laser pulses of 4-meV spectral width tuned in resonance with the e₁h₁ heavy-hole QW exciton resonance.

© 1995 Optical Society of America