Vertical transport in all-binary GaAs/AlAs short-period superlattices and carrier trapping and detrapping dynamics by different quantum wells

摘要

Dynamics of vertical transport in all-binary GaAs/AlAs short-period superlattices (SPSs) have been investigatedas a function of temperature by steady-state and time-resolved photoluminescence (PL) experiments.When two different, enlarged quantum wells are embedded in the SPSs, photoexcited carrierscompete to be trapped into various localized exciton states and a variety of exciton radiative recombinationdynamics appears accompanied by phonon heating. Redistribution of carrier population in the differentwells by phonon scattering is significantly influenced by vertical miniband transport in the SPSs.Three different transport regimes are pointed out: (i) tunneling transport affected by irreversible carriercooling into deep localized states, (ii) interplay of carrier relaxation and phonon-assisted activation mediatedby an efficient miniband Bloch transport, and (iii) thermalization processes.