Bent Polytypic ZnSe and CdSe Nanowires Probed by Photoluminescence

Nanowires (NWs) have witnessed tremendous development over the past two decades owing to their varying potential applications. Semiconductor NWs often contain stacking faults due to the presence of coexisting phases, which frequently hampers their use. Herein, it is investigated how stacking faults affect the optical properties of bent ZnSe and CdSe NWs, which are synthesized using the vapor transport method. Polytypic zinc blende-wurtzite structures are produced for both these NWs by altering the growth conditions. The NWs are bent by the mechanical buckling of poly(dimethylsilioxane), and micro-photoluminescence (PL) spectra were then collected for individual NWs with various bending strains (0-2%). The PL measurements show peak broadening and red shifts of the near-band-edge emission as the bending strain increases, indicating that the bandgap decreases with increasing the bending strain. Remarkably, the bandgap decrease is more significant for the polytypic NWs than for the single phase NWs. This work provides insights into flexible electronic devices of 1D nanostructures by engineering the polytypic structures.