Negative Persistent Photoconductivity in Unintentionally Doped n-Type GaN
非故意掺杂n型GaN的负持续光电导现象

The persistent photoconductivity effect in unintentionally doped n-GaN grown by metal organic chemical vapor deposition (MOCVD) is presented.The photoconductivity build-up and its decay behavior with different excitation intensities and different wavelength ranges are observed.The experiment shows persistent photocurrent (PPC),negative photocurrent (NPC),and negative persistent photocurrent (NPPC) trends as the excitation intensity is changed from low to high when the excitation light includes wavelengths larger than the absorption edge of GaN.It is believed that the phenomenon is ruled by competition between capture and release photo-generated electrons and holes by deep electron traps and deep hole traps,respectively.