Plasma Treatment over ZnO/MgO Core/Shell Nanowires for the Enhancement of UV Exciton Emission

DI DONATO, ANDRES; COMEDI, DAVID MARIO; VEGA, NADIA CELESTE; STEREN, LAURA BEATRIZ; ZELAYA, MARÍA PRISCILA; BONAPARTE, JUAN; TIRADO, MONICA CECILIA

AVEIRO

Congreso; ADVANCED NANO MATERIALS 2019; 2019

ZnO is a semiconductor with exceptional properties when compared to other direct band gap semiconductors, as it exhibits an exciton binding energy of ~60 meV and a band gap width in the UV of ~3.3 eV. These properties make ZnO usable for development of high temperature ultraviolet (UV) optoelectronic devices [1]. Recently, great efforts were invested in the development of light emitting devices, sensors and lasers, using ZnO nanowires (NWs). However, due to the high surface-to-volume ratio, properties of ZnO NW ensambles are generally much more impacted by surface defects, such as oxygen vacancy and dangling bond, than those of bulk ZnO.To enhance the UV emission intensity, different materials have been proposed to act as a NW surface passivating shells. The UV emission improvement in MgO shell passivated ZnO NWs was reported in recent years [1]. In this work, a novel plasma treatment over ZnO/MgO core/shell nanostructures is proposed, in order to improve control of the MgO shell thickness.After a certain time of exposure to the plasma, a significant increase of ultraviolet-to-visible ratio intensity was observed.