Origin of green luminescence in hydrothermally grown ZnO single crystals

Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics letters 2015-06, Vol.106 (25)
Main Authors: Čížek, J., Valenta, J., Hruška, P., Melikhova, O., Procházka, I., Novotný, M., Bulíř, J.
Format: Article
Language:English
Subjects:
ANNEALING
Applied physics
Cadmium
Clean energy
COLOR
Conduction bands
Crystal growth
Crystals
Electron recombination
EV RANGE
HYDROGEN
Lattice vacancies
Luminescence
MATERIALS SCIENCE
MONOCRYSTALS
OXYGEN
PHOTOLUMINESCENCE
Positron annihilation
RECOMBINATION
Single crystals
STOICHIOMETRY
VACANCIES
VAPORS
ZINC
Zinc oxide
ZINC OXIDES
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Combining photoluminescence and positron annihilation studies of hydrothermally grown ZnO crystals with stoichiometry varied by controlled annealing enabled us to clarify the origin of green luminescence. It was found that green luminescence in ZnO has multiple origins and consists of a band at 2.3(1) eV due to recombination of electrons of the conduction band by zinc vacancy acceptors coupled with hydrogen and a band at 2.47(2) eV related to oxygen vacancies. The as-grown ZnO crystals contain zinc vacancies associated with hydrogen and exhibit a green luminescence at 2.3(1) eV. Annealing in Zn vapor removed zinc vacancies and introduced oxygen vacancies. This led to disappearance of the green luminescence band at 2.3(1) eV and appearance of a green emission at higher energy of 2.47(2) eV. Moreover, the color of the crystal was changed from colorless to dark red. In contrast, annealing of the as-grown crystal in Cd vapor did not remove zinc vacancies and did not cause any significant change of green luminescence nor change in coloration.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4922944