Research Article

Sonochemical Synthesis of -Doped ZnO Nanospheres with Enhanced Upconversion Photoluminescence

Figure 2

(a) SEM, (b) TEM, and (c) HRTEM images of the as-prepared -doped ZnO nanospheres with Er doping concentration of 2%.
317857.fig.002a
(a)
317857.fig.002b
(b)
317857.fig.002c
(c)