We have studied electrical transport phenomena after ion implantation in sublimed C60films. A n type doping exists with 30 KeV potassium ion irradiations and low fluences (D < 1015ions/cm2). However degradation effects have been noted. So we have tried to discriminate doping and damage effects. Studies about the compensation phenomenum have been performed in order to prove the chemical role of the potassium atoms. An electron transfer from the alkali metal is sure; but a strong competition exists between degradation and doping phenomena. Finally, the intact C60molecules are the insulator barriers, K3C60and isolated carbon atoms are the conductor phase for an heterogeneous media model.