Reduced bound exciton and surface exciton emissions in Al-doped ZnO nanorods exposed to ambient air

Abstract

Temperature-dependent photoluminescence (PL) spectroscopy is employed to investigate the effects of exposure to ambient air on the optical property of Al-doped ZnO nanorods. Low temperature PL of the as-grown nanorods shows dominant D0 X (excitons bound to neutral donors) emission at 3.363 eV and surface state-related emission at 3.310 eV. After exposure to ambient air, both of them vanish and the first LO phonon replica of free exciton is observed instead. It is proposed that surface adsorption and indiffusion of oxygen in ambient air result in surface modification and destruction of D0 X complex. © 2008 American Institute of Physics.