Stopping power of He, C and O in GaN

GaN and other group III nitrides based alloys are important materials in optoelectronic and electronic devices, including high-brightness blue and white LEDs, multi-junction solar cells, high-frequency transistors, and THz emitters. Unintentional impurities can be present, with a strong influence in the properties of these materials. These impurities are often light elements such as H, C, or O, and an ion beam analysis technique such as heavy ion elastic recoil detection analysis can play a fundamental role in their quantification. However, to our knowledge stopping powers in GaN have not yet been measured, and data analysis relies on using the Bragg rule, which is often inaccurate. We have used a bulk method, previously developed by us and applied successfully to other systems, to determine experimentally the stopping power of 4He, 12C and 16O in GaN, in the energy ranges 0.6–2.3, 0.9–14.9, and 0.6–14.9 MeV, respectively. The results of our measurements and bulk method analysis are presented.