We have tested Bi for rhe surfactant mediated epitaxy of Ge on Xl 1 I). Manding of Ge is prevented and a ZD layer growth of smooth and continuous Ge films is observed. The lattice mismatch is accommodated by a periodic array of dislocations confined to the Sib3 interface. The large covalent radius of Bi reduces the binding energy, allovkg very efficient segregation and Ion doping levels even at low growth temperatures. Unfortunately, this results also in a high Bi desorprion flux Limiting the possible growth temperatures bzIow 600°C. Consequently the Ge films show a high defect density in the order of IO* cm-’ for stacking faults and 10” cm-’ for dislocations uphich limit eiecuon Hail mobility to values beiow 700 cm’/V s at room temperature.