Photo-generated carriers decay behavior of nano-crystalline β-SiC thin film grown at different substrate bias voltage

The photo-generated carriers decay behavior of nanocrystalline β-SiC film grown by helicon wave plasma-enhanced chemical vapor deposition process at different substrate bias voltage is measured by microwave absorption technique. The probability of nanosecond fast decay of the photo-generated carriers concentration increases with substrate bias. The fast decay of photo generated carriers related to the radiative recombination process and substrate bias led to an increase in trap depth in the slow decay. The decay of nano-SiC thin films at different substrate bias voltage with different time constant indicates that the increase of substrate negative bias led to the increase in the density of deep trap levels and different trap level position related to different decay time. Photo-carrier transient behavior is closely related to the film microstructure, The high defect states density of nano-silicon carbide grain boundary lead to carriers trapping probability increase and the nonradiative recombination probability decreases.