Growth of II-VI semiconductor nanostructures

Zn1-xMnxTe (0 ≤ x ≤ 0.12) quantum dots (QDs) were grown on the Zn1-yMnySe (0 ≤ y ≤ 0.05) buffer layer by alternating supplying and conventional molecular beam epitaxy (MBE). The formation of Zn1-xMnxTe QDs was confirmed by the atomic force microscopy (AFM) measurements and reflection high energy electron diffraction (RHEED) patterns. For the atomic smooth buffer layers, the Stranski-Krastanov (SK) growth mode was observed. On the other hand, the Zn1-xMnxTe QDs could also be grown by the Volmer Weber (VW) island growth mode on the rough buffer layer. The shape of ZnTe QDs is cone shape with a typical radius of several tenths (10 to 50) nm and height of a few (1 to 8) nm. The dot density ranges from 108/cm2 to 1010/cm2. The size distribution is found to be heavily tailed. The photoluminescence (PL) study showed that the band alignment of the Zn1-xMnxTe/Zn1-yMnySe QD system is type II. The carrier capture times were 7 and 38 PS for the VWand SK ZnTe/ZnSe QDs.