The stability of μc-Si:H materials for solar cells is well researched.The dependence of light-sensitivity as well as the sub gap absorption on light soaking time is monitored.The results clearly show that the magnitude of relative light induced degradation is closely related to the material structure.Amorphous fraction is the key factor to light induced degradation.The magnitude of relative efficiency degradation increases with the amorphous fraction.The more the amorphous fraction in material,t...