Abstracts Book - IMRC 2018

• SF2-P060
STRUCTURAL TRNASFORMATIONS IN UNDOPED AND Tb 3+ DOPED
ZnO FILMS GROWN BY RF MAGNETRON SPUTTERING ON Si
SUBSTRATES
Tetyana Kryshtab 1 , Lyudmyla Borkovska 2 , Oleksandr Kolomys 3 , Victor Strelchuk 3 , X. Portier 4 ,
Roberto Benjamín Cortés Herrera 5
1 Instituto Politécnico Nacional - IPN, Department of Physics, Mexico. 2 V.Lashkaryov Institute of
Semiconductor Physics at the National Academy of Sciences of Ukriane, Laboratory of
photoelectric phenomena in semiconductors, Ukraine. 3 V.Lashkaryov Institute of
Semiconductor Physics at the National Academy of Sciences of Ukriane, Laboratory of Optical
Submicron Spectroscopy, Ukraine. 4 CIMAP/CEA/CNRS/Ensicaen/UCBN, UNICAEN, France.
5 Instituto Politécnico Nacional - IPN, ENCB, Mexico.
ZnO is a wide band gap semiconductor that found both light-emitting and
photovoltaic applications owing to its large exciton binding energy, high electron
mobility and transparency in the visible spectra range. According to its
properties, ZnO seems to be promising as the host material for different RE 3+
(rare earth) ions. However, incorporation of RE 3+ ions into Zn 2+ place faces
problems due to large difference in the ionic radius and different charge state
of these ions.
In this report, the structural and optical properties of nominally undoped and
doped with Tb 3+ ions thin films of ZnO were investigated. The films of 200 nm
and 600 nm thicknesses were grown by RF magnetron sputtering on (100) Si
substrate at 100 °C and subjected to post-deposition thermal treatment at
temperatures in the range of 300-900 °C. The rapid thermal annealing (RTA) for
5 s and conventional thermal annealing (CTA) for 1 h were used. The EDX study
showed Tb concentration in the films to be about 4 %.
X-ray diffraction (XRD) patterns showed strong preferred orientation along the
c-axis of ZnO perpendicular to the substrate. The as-deposited films were under
tensile strains along the c-axis, the strains being larger for Tb-doped ZnO. The
micro-Raman spectra of ZnO films revealed tensile strains in the plane of the
substrate for doped samples and compressive strains for the undoped ones.
These data imply the incorporation of Tb ions into ZnO film resulted in lattice
deformation (stretching). The XRD data also show that the incorporation of Tb
into ZnO hinders the grain growth. In the Tb-doped ZnO, the grain size was
about 10 nm, while in the undoped it was about 30 nm. The PL spectra of the
films contain the UV bands ascribed to near band edge and defect-related PL of