Effect of Doping and Morphology on UV Emission in Low-Dimensional ZnO:Na Structures

CECILIA ZAPATA; SIMONELLI, GABRIELA; SILVIA PEREZ DE HELUANI; BRIDOUX, GERMAN; MANUEL VILLAFUERTE; CLAUDIA RODRÍGUEZ TORRES; B. STRAUBE; FERREYRA, JORGE M.; PABLO ESQUINAZI

PHYSICA STATUS SOLIDI B-BASIC RESEARCH

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2018 vol. 255 p. 1800056 - 1800056

0370-1972

Band-edge photoluminescence of zinc oxide materials reveals a phononassistedultraviolet emission enhanced by Na doping. We report thesynthesis of ZnO and Na-doped ZnO, the changes in structure and opticalproperties as a function of doping concentration and synthesis temperature.The obtained samples are nanoneedles, microparticles, and microwires. Thestructural effect of Na doping is studied by X-ray diffraction and Ramanspectroscopy. Room temperature photoluminescence reveals a contributionof band bending at the surface of the nanostructures, decreasing with Naconcentration. Franz?Keldysh effect predicts strong electric field localized inthe depletion region and appears to be the cause of red-shift in UV bandemission of nanoneedles in comparison to microwires. Our results indicatethat Na doping introduces an acceptor level between 150 and 200meVabove the valence band.