ESR investigations on hydrogen-induced hyperfine splitting features in ZnO

Low temperature X-band electron spin resonance measurements (ESR) were performed on as-grown and post-hydrogenated zinc oxide (ZnO) single crystals. As-grown ZnO exhibits a single strong line at g=1.957g=1.957 that was identified as hydrogen. In contrast, post-hydrogenated ZnO shows a distinctly different ESR spectrum. Besides the intensification of the hydrogen donor line, hydrogenation triggers the observation of additional hyperfine lines. They are attributed to manganese (Mn) impurities probably introduced from the growth process. From the ESR data a Mn concentration of 6×1013 cm−3 was estimated.