A sputtered phase-change material, Ge 10 Sb 90 , processed into dots with a height and diameter of 50 nm, shows rapid crystallization triggered by 300 ps laser excitation. Crystallization takes place with a short time delay of approximately 70 ns for a sample with Sb seed layers. The delay becomes just 15-20 ns when a NiCr layer is provided to control the heating-cooling profi le. The nanodot sample requires less energy for crystallization, with a large optical change equivalent to that of the blanket fi lm. These results demonstrate that the nanodot phase-change material could be a possible candidate for next-generation "green" optical storage.Adv. Optical Mater. 2013, 1, 820-826 821 wileyonlinelibrary.com