We report rapid crystallization of GeTe- Bi2 Te3 mixed layers. The as-deposited (GeTe)1-x (Bi2 Te3)x (GBT) layers with x>0.5 are fcc crystalline, while the layers with x<0.5 are amorphous, for cosputter deposition at room temperature. We found that Bi2 Te3 significantly enhances the crystallization of the GBT layers. Furthermore, both temperature and minimum time required for crystallization (Tc and tc,min) of GBT layers are smaller than those of (GeTe)1-x (Sb2 Te3)x (GST) layers. For example, crystallization of GBT layer with x=0.12 occurs at 155.0 °C within 30.9 ns, which is around 13 of 95.7 ns for Ge2 Sb2 Te5 with Tc =168.5 °C.