摘要
研究了MOCVD方法制备的非故意掺杂n型GaN薄膜的持续光电导现象.实验发现样品的光电导与入射光强有密切的关系,当入射光强由弱到强变化时,样品会依次出现正常持续光电导(PPC)、负光电导(NPC)和负持续光电导(NPPC)现象.据知,这是首次在一个样品中仅仅通过改变入射光强就可以依次产生以上现象的实验报道.通过系统的实验分析和理论研究认为,该现象形成的主要原因是材料中深能级电子陷阱和空穴陷阱共同作用的结果.
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,re-spectively.
