Determination of the Wurtzite and Zincblende Fractions in II-VI Semiconductor Nanowires

We present a detailed powder X-ray diffraction (p-XRD) and transmission electron microscopy (TEM) study to explore the structural properties of CdS, CdSe, and CdTe semiconductor nanowires (NWs) grown by the solution-liquidsolid (SLS) method. The SLS method yields easily dispersible NWs with a controllable diameter and polytypic crystal structure. The different samples exhibit different wurtzite (WZ) and zincblende (ZB) fractions, which are investigated by high-resolution TEM of selected wires with distinct crystallographic orientations, and also by p-XRD of a large amount of NWs. In combination with atomistic models containing up to one million atoms, we calculate diffraction patterns based on the kinematic theory of diffraction. We show that the ZB-rate in WZ-rich NWs can be directly determined from relative reflex intensities in the experimental p-XRD data.