The persistent photoconductivity (PPC) behavior has been characterized in sputtered GaN thin films using the room illumination with a wavelength of 254 nm under a 5-V bias. It was found that the N2 partial pressure in the sputtering atmosphere has an evident effect on the PPC behavior. The obtained data show that the nitrogen vacancy is the candidate for PPC effect in the sputtered GaN film. At lower N2 partial pressures, the nitrogen vacancy can be induced and resulted in GaN films with more donor levels as compared with those of samples deposited at higher N2 contents. An energy band model that can account for the experimental observation of PPC behavior is proposed.
- Persistent photoconductivity