Origin of green luminescence in hydrothermally grown ZnO single crystals

0449051 - FZÚ 2016 RIV US eng J - Journal Article
Čížek, J. - Valenta, J. - Hruška, P. - Melikhova, O. - Procházka, I. - Novotný, Michal - Bulíř, Jiří
Origin of green luminescence in hydrothermally grown ZnO single crystals.
Applied Physics Letters. Roč. 106, č. 25 (2015), "251902-1"-"251902-4". ISSN 0003-6951. E-ISSN 1077-3118
R&D Projects: GA ČR(CZ) GAP108/11/0958
Institutional support: RVO:68378271
Keywords : defects * dependence * acceptor * vacancy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.142, year: 2015

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.
Permanent Link: http://hdl.handle.net/11104/0250646