engleski

Sequential swift heavy ion irradiation of gallium nitride

Damage introduced by swift heavy ions into radiation hard materials is a concept of large interest which still remains only partially understood. The basic principle by which defects are produced consists of the formation of ion tracks on the surface or in the bulk of the material. It is important to investigate the impact of swift heavy ion irradiation on these materials, with GaN being a prominent example, because there is a possibility of damage build-up in the material which leads to complex behaviour, especially in radiation harsh environments. Furthermore, dynamics of damage formation during doping by ion implantation is also an important issue [1], since the efficacy of implantation can be improved if other processes occurring simultaneously are controlled or suppressed. In our previous study [2], we found no evidence of ion track formation in the bulk after swift heavy ion irradiation using 23 MeV I and 90 MeV Xe beams. However, recently we were able to introduce additional disorder into moderately damaged GaN crystals using the same 23 MeV Iodine and 90 MeV Xe beams in cases where GaN samples have been pre-irradiated with 2 MeV Au or with 900 MeV Xe ion beams. Two different ion beams are expected to introduce damage into GaN via nuclear and electronic stopping, respectively [3]. Moreover, sequential ion irradiation of GaN has not been investigated so far. In this contribution, we report new results of sequential ion irradiation of GaN based on the RBS/c, TEM and AFM measurements.

swift-heavy-ions ; ion-tracks ; gallium-nitride ; defects

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