Open AccessMicroscopic origins of the surface exciton photoluminescence peak in ZnO nanostructures
Author(s) -
Mahua Biswas,
Yun Suk Jung,
Hong Koo Kim,
Kumarappan Kumar,
Gregory Hughes,
S. B. Newcomb,
M.O. Henry,
Enda McGlynn
Publication year - 2011
Publication title -
physical review. b, condensed matter and materials physics
Language(s) - English
Resource type - Journals
eISSN - 1538-4489
pISSN - 1098-0121
DOI - 10.1103/physrevb.83.235320
Subject(s) - photoluminescence , exciton , x ray photoelectron spectroscopy , nanostructure , materials science , desorption , adsorption , transmission electron microscopy , spectroscopy , oxygen , analytical chemistry (journal) , surface photovoltage , ultra high vacuum , chemical physics , nanotechnology , optoelectronics , condensed matter physics , chemistry , nuclear magnetic resonance , physics , organic chemistry , quantum mechanics , chromatography
We report photoluminescence (PL) studies of the surface exciton peak in ZnO nanostructures at ∼3.367 eV aimed at elucidation of the nature and origin of the emission and its relationship to the nanostructure morphology. PL spectra in conjunction with localized voltage application in high vacuum and different gas atmospheres show a consistent variation (and recovery), allowing an association of the PL to a bound excitonic transition at the ZnO surface, which is modified by an adsorbate. PL studies of samples treated by plasma and of samples exposed to UV light under high vacuum conditions, both well-known processes for desorption of surface adsorbed oxygen,\udshow no consistent effects on the surface exciton peak indicating the lack of involvement of oxygen species.\udX-ray photoelectron spectroscopy data strongly suggest involvement of adsorbed OH species. X-ray diffraction,\udscanning, and transmission electronmicroscopy data are presented also, and the relationship of the surface exciton\udpeak to the nanostructure morphology is discussed