Room temperature plasma hydrogenation – An effective way to suppress defects in ZnO nanorods

The densely packed, perpendicularly oriented ZnO nanorods were hydrothermally grown in dark and under UV irradiation on fused silica glass substrates seeded by ZnO nanocrystals. The exciton-related UV photoluminescence observed at room temperature at 380 nm increased significantly after a room temperature hydrogen plasma treatment in a negatively self-biased capacitive coupled radio frequency reactor whereas the defect-related yellow photoluminescence was noticeably reduced together with the F+ electron paramagnetic resonance (EPR) signal g = 1.96. Thus, the F+ EPR signals are surface type defects which amount is governed by the surface plasma treatment. The correlation between PL and EPR signals observed in ZnO nanorods exposed to the same treatment relates some optically active defects to paramagnetic centers.