In-plane photocurrent of self-assembled InxGa1-xAs/GaAs(311)B quantum dot arrays - art. no. 085303

摘要

On self-assembled InxGa1-xAs/GaAs(311)B quantum dots (QD's), photocurrent in the plane of QD arrays was measured under irradiation with wavelengths longer than 850 nm (1.46 eV). A sample with rather inhomogeneous QD sizes shows hopping conduction, indicating the localization of carriers in individual QD's. A two-dimensional QD superlattice, consisting of highly ordered and homogeneously sized QD's, exhibits negative differential conductance (NDC), i.e., photocurrent decrease with increasing applied voltage, in a limited electric-field range. The pre-NDC conduction is argued to arise from the miniband, which is evidenced by the photoluminescence, while the post-NDC conduction is found to tie hopping as in a localized QD system, suggesting a miniband destruction under an in-plane electric field as low as similar to 10(3) V cm(-1). The miniband transport is likely controlled by two-dimensional acoustic-phonon scattering. [References: 33]