Shape and property control of Mn doped ZnSe quantum dots: from branched to spherical

Abstract

A simple method is reported to achieve shape control of Mn doped ZnSe quantum dots from branched to spherical through control of the zinc precursor and the temperature of injection. High resolution transmission electron microscopy (HRTEM) is used to investigate the crystallinity of the quantum dots. Photoluminescence (PL) spectroscopy and UV-vis-absorption have been used to correlate PL properties and quantum yield of the quantum dots with their structure. The crystal phase of Mn doped ZnSe quantum dots can be controlled from zinc blende to wurtzite by simply changing the injection rate of the zinc precursor. We show that the photoluminescence properties are influenced by the structure of quantum dots. Spherical wurtzite type Mn doped ZnSe quantum dots have the highest quantum yield compared with other shapes or crystal phases of dots grown in similar reactions.