Coherent optical nonlinearities and phase relaxation of quasi-three-dimensional and quasi-two-dimensional excitons in ZnSxSe1-x/ZnSe structures

Article

关键词: MULTIPLE-QUANTUM-WELLS;    4-WAVE-MIXING SIGNALS;    POLARIZATION DEPENDENCE;    PHOTON-ECHOES;    GAAS;    SEMICONDUCTORS;    ZNSE;    LINEWIDTHS;    DISORDER;    SPECTROSCOPY;   

DOI  :  10.1103/PhysRevB.56.12581

来源: SCIE

【 摘 要 】

We investigate the dephasing of heavy-hole excitons in different free-standing ZnSxSe1-x/ZnSe layer structures by spectrally resolved transient four-wave mixing. ZnSe layers of 80, 8, and 4 nm thickness with ternary barriers are studied, representing the crossover from quasi-three-dimensional to quasi-two-dimensional excitons. A common feature of the four-wave-mixing signals is the appearance of two components, a prompt signature and a delayed photon echo, which are identified by their different polarization dependencies and decay times. For crosslinear polarized fields, the rapidly decaying signal is attributed to the response of spin-coupled exciton states, with a decay time given by the inhomogeneous broadening. The photon echo is due to a distribution of localized, noninteracting excitons. We determine the exciton-exciton and exciton-phonon scattering cross sections for different dimensionalities by the intensity and temperature dependencies of the exciton dephasing.

【 授权许可】

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