Self-organized quantum dots of zinc-blende MnTe grown by molecular beam epitaxy

Abstract

The successful growth by molecular beam epitaxy (MBE) of self-organized quantum dots (QDs) of zinc-blende (ZB) MnTe onto CdTe(1 0 0) is reported. Mn and Te fluxes were supplied either simultaneously (conventional MBE) or alternately (atomic layer epitaxy — ALE) onto the surface to form MnTe. Atomic-force microscope measurements for uncapped samples revealed that cone-shaped dots were formed in both of the two growth methods, however with different sizes. The diameter and the height are, respectively, given typically by D = 140 ± 10 nm and h = 70 ± 10 nm in QDs grown by conventional MBE, and by D = 60 ± 5 nm and h = 8 ± 1 nm in QDs grown by ALE. In photoluminescence (PL) and time-resolved PL measurements, a broad emission band due to the Mn 2+ d—d transition was observed at 2.02 eV. Its decay time was found to be of the order of several tens to hundreds of nanoseconds, which is shorter than those from ZBMnTe films by two or three orders.