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-liquid-solid (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.

By combining an atomistic valence-force field approach and calculations based on the effective-mass approximation we investigate the influence of strain effects on the band alignment and general excitonic properties of core/shell CdSe/CdS dot/rod nanoparticles. We find that the inclusion of strain effects leads to an increase in exciton energy as well as to a decrease in electron and hole wave function overlap. Importantly, the native type-I band alignment of the CdSe/CdS material system is preserved and does not change into an quasi-type-II or even type-II band offset for the nanoparticles. Furthermore, we analyze the impact of strain on the spectral diffusion of the fluorescence emission of these nanoparticles, which is explained by migrating surface charges. Our calculations show that the addition of strain effects leads to increased energy shifts as well as larger changes in the squared electron and hole wave function overlap, while the correlation of both also exhibits a steeper slope than for the unstrained system. For a given CdSe core size, an increase in CdS-shell thickness decreases the possible ranges of energy shift and squared wave function overlap without changing the slope of their correlation. On the other hand, for a given nanoparticle overall thickness, dot/rod systems with a small CdSe core exhibit the strongest influenceability by surface charges.