TY - JOUR

T1 - On the nature of the effect of adsorbed oxygen on the excitonic photoluminescence of ZnO

AU - Lisachenko, A.A.

AU - Titov, V.V.

AU - Akopyan, I.K.

AU - Labzowskaya, M.E.

AU - Novikov, B.V.

PY - 2018/3

Y1 - 2018/3

N2 - The mechanism of the effect of adsorbed oxygen on photoluminescence (PL) of ZnO powders and ZnO/Si ALD films in the UV–VIS regions was studied, simultaneously with the in-situ UV photoelectron spectroscopy (UPS) and mass spectrometry (MS) measurements. We have found a drastic (up to 10 times) increase of the exciton PL along with a slight (by ~ 1.5 times) increase of green PL induced by thermo-reducing of ZnO surface in H 2 or CO atmosphere or by a UV–VIS photo-reducing in the vacuum. The reaction products H 2O, CO 2 and photo-desorbed O 2 were registered by the MS. According to UPS (8.43 eV), the change in PL is accompanied by a significant change in the surface dipole value δ without shift of the Fermi level E F or of the band bending V S. We believe that the slow surface states interact with the adsorbed oxygen and thus create a surface 2D-quantum well whose internal field destroys the excitons. The internal fast surface states not interacting with the slow ones provide a pinning of the Fermi level and the stability of the band bending value. The adsorbed oxygen also affects the surface defects thus reducing the VIS luminescence of ZnO.

AB - The mechanism of the effect of adsorbed oxygen on photoluminescence (PL) of ZnO powders and ZnO/Si ALD films in the UV–VIS regions was studied, simultaneously with the in-situ UV photoelectron spectroscopy (UPS) and mass spectrometry (MS) measurements. We have found a drastic (up to 10 times) increase of the exciton PL along with a slight (by ~ 1.5 times) increase of green PL induced by thermo-reducing of ZnO surface in H 2 or CO atmosphere or by a UV–VIS photo-reducing in the vacuum. The reaction products H 2O, CO 2 and photo-desorbed O 2 were registered by the MS. According to UPS (8.43 eV), the change in PL is accompanied by a significant change in the surface dipole value δ without shift of the Fermi level E F or of the band bending V S. We believe that the slow surface states interact with the adsorbed oxygen and thus create a surface 2D-quantum well whose internal field destroys the excitons. The internal fast surface states not interacting with the slow ones provide a pinning of the Fermi level and the stability of the band bending value. The adsorbed oxygen also affects the surface defects thus reducing the VIS luminescence of ZnO.

KW - Mass-spectrometry

KW - Oxygen thermo/photo-desorption

KW - Powders and ZnO/Si ALD films

KW - Superficial 2D-quantum well

KW - UV–VIS Photoluminescence

KW - Zinc oxide

KW - DEFECTS

KW - ELECTRON

KW - NANOPARTICLES

KW - FILMS

KW - LUMINESCENCE

KW - SURFACE

KW - EMISSION

KW - ATOMIC LAYER DEPOSITION

KW - UV-VIS Photoluminescence

UR - http://www.scopus.com/inward/record.url?scp=85034759827&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/nature-effect-adsorbed-oxygen-excitonic-photoluminescence-zno

U2 - 10.1016/j.jlumin.2017.11.022

DO - 10.1016/j.jlumin.2017.11.022

M3 - Article

VL - 195

SP - 153

EP - 158

JO - Journal of Luminescence

JF - Journal of Luminescence

SN - 0022-2313

ER -