氢化作用对低能电子束辐照下GaN发光演变的影响

结合氢在GaN中的扩散特性，运用阴极荧光（CL）谱，对氢化前后低能电子束辐照下GaN带边发光强度的演变进行了研究.实验发现，氢化前GaN在低能电子束辐照下带边发光强度呈现衰减的趋势，而氢化后带边发射强度先上升后衰减，而且氢化后的衰减比氢化前弱.1 h辐照过程中，氢化后GaN带边发光强度的变化比氢化前要小很多.另外，实验中发现经过氢化处理的GaN在辐照后20 h内没有观察到带边发射强度的恢复.研究表明氢原子在GaN中可以钝化缺陷来增强发光，但这种钝化缺陷的作用必须通过克服高的扩散势垒来实现，而低能电子束可以 关键词： 阴极荧光 低能电子束 氢化 演变

Effect of hydrogenation on the luminescence evolution of GaN under low energy electron beam irradiation

Luminescence evolution of GaN irradiated by low energy electron beam before and after hydrogenation has been investigated by means of cathodoluminescence (CL), in connection with the diffusion properties of hydrogen in GaN. It is found that under low energy electron beam irradiation, the band to band emission of GaN shows a decrease before hydrogenation, while it shows an initial increase and a subsequent decrease after hydrogenation, and the decrease after hydrogenation is relatively weak. Moreover, there is no luminescence recovery in 20 hours after the first irradiation after hydrogenation. The experimental results indicate a luminescence enhancement effect of hydrogen by passivating certain defects in GaN. However, such effect must be realized by overcoming high migration barrier in GaN. In the experiments, low energy electron beam supports enough energy to hydrogen to diffuse and passivate defects in CaN. These results show strongly the importance of diffusion of hydrogen in the passivation process in semiconductors.