Investigation on Persistent Photoconductivity Effect in Cubic GaN
立方相GaN的持续光电导

The persistent photoconductivity (PPC) effect in unintentional doped cubic GaN grown on GaAs(001) substrate by metalorganic chemical vapor deposition (MOCVD) is studied.It is widely accepted that the PPC effect in hexagonal GaN is related to the yellow luminescence (YL).However,we observe that in cubic GaN,it is induced by the unintentionally incorporated hexagonal crystallites in cubic matrix and has nothing to do with YL.We suggest that the spatial carrier separation caused by the barrier between the cubic matrix and hexagonal crystallites is the reason of the PPC effect.A barrier-limited model is developed to analyze the decay process,and the decay kinetics is discussed.The result of data fitting confirms our model and conclusion.