Light induced metastable defect creation and annealing kinetics in he-diluted pecvd amorphous silicon films

Helium diluted amorphous silicon films were deposited in a home made glow discharge system by varying substrate temperature, dilution ratio, rf power and total chamber pressure. Stability of one of the films that shows best optoelectronic properties in terms of the fabrication of heterojunction solar cells was investigated through optical transmission, photon flux dependent steady state photoconductivity and CPM (Constant Photocurrent Method) measurements. Light induced metastable defect creation and annealing kinetics of the film is similar to that of a-Si:H films deposited using silane gas only. On the other hand, photoconductivity saturates much quickly during the degradation