Single-Crystal MgO Hollow Nanospheres Formed in RF Impulse Discharge Plasmas

Figure 7

Cooling process of nanoparticles. Liquid, solid, and gas regions are drawn by grey, black, and white, respectively. (a) Liquid MgO droplets with spherical shape. (b) Outer surface starts being cooled down to form MgO crystal by collecting Mg atoms from the central core. (c) The crystallization proceeds toward the core by expelling excess oxygen toward the centre. (d) Hollow nanosphere of single crystal MgO.