Fig. 3

Modulation of geometric parameters in QDNWs. a, b Representative TEM images (a, from left to right) and the corresponding diameter distributions (b) of CdS–ZnS QDNWs grown at temperature of 190 °C, 210 °C, 230 °C, and 250 °C, respectively. c Time dependence of nanowire length for QDNWs with different initial ZnS growth time. Error bars in c correspond to standard deviation values of each newly grown ZnS segment. d (Left panel) Dark-field STEM image of QDNWs with modulated spacings of CdS QDs. (Right panel) The spacing of two adjacent CdS QDs (i.e., ZnS length) versus ZnS growth time. Error bars in d correspond to standard deviation values of each newly grown ZnS segment. e Representative STEM image of an ultralong QDNW with 10 CdS QDs (i.e., 21 segments in total). Scale bars are 20 nm, 50 nm, and 20 nm for a, d, and e, respectively