Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma

The study explores the optical and transport properties of polycrystalline ZnO thin films prepared using reactive pulsed mid-frequency sputtering with RF electron cyclotron wave resonance (ECWR) plasma. This deposition method increases the ionization degree of sputtered particles, the dissociation o...

Full description

Saved in:
Bibliographic Details
Main Authors: Zdeněk Remeš, Zdeněk Hubička, Pavel Hubík
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Nanomaterials
Subjects:
Online Access:https://www.mdpi.com/2079-4991/15/8/590
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850180448709246976
author Zdeněk Remeš
Zdeněk Hubička
Pavel Hubík
author_facet Zdeněk Remeš
Zdeněk Hubička
Pavel Hubík
author_sort Zdeněk Remeš
collection DOAJ
description The study explores the optical and transport properties of polycrystalline ZnO thin films prepared using reactive pulsed mid-frequency sputtering with RF electron cyclotron wave resonance (ECWR) plasma. This deposition method increases the ionization degree of sputtered particles, the dissociation of reactive gas and the plasma density of pulsed reactive magnetron plasma. Optical absorption spectra reveal a sharp Urbach edge, indicating low valence band disorder. Lattice disorder and deep defect concentration are more likely to occur in samples with higher roughness. PL analysis at low temperature reveals in all samples a relatively slow (μs) red emission band related to deep bulk defects. The fast (sub-ns), surface-related blue PL band was observed in some samples. Blue PL disappeared after annealing in air at 500 °C. Room temperature Hall effect measurements confirm n-type conductivity, though with relatively low mobility, suggesting defect-related scattering. Persistent photoconductivity was observed under UV illumination, indicating deep trap states affecting charge transport. These results highlight the impact of deposition and post-treatment on polycrystalline ZnO thin films, offering insights into optimizing their performance for optoelectronic applications, such as UV detectors and transparent conductive oxides.
format Article
id doaj-art-291d0c2eae8f4d2b9cdc7054b132b34d
institution OA Journals
issn 2079-4991
language English
publishDate 2025-04-01
publisher MDPI AG
record_format Article
series Nanomaterials
spelling doaj-art-291d0c2eae8f4d2b9cdc7054b132b34d2025-08-20T02:18:10ZengMDPI AGNanomaterials2079-49912025-04-0115859010.3390/nano15080590Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR PlasmaZdeněk Remeš0Zdeněk Hubička1Pavel Hubík2FZU—Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech RepublicFZU—Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech RepublicFZU—Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 00 Prague, Czech RepublicThe study explores the optical and transport properties of polycrystalline ZnO thin films prepared using reactive pulsed mid-frequency sputtering with RF electron cyclotron wave resonance (ECWR) plasma. This deposition method increases the ionization degree of sputtered particles, the dissociation of reactive gas and the plasma density of pulsed reactive magnetron plasma. Optical absorption spectra reveal a sharp Urbach edge, indicating low valence band disorder. Lattice disorder and deep defect concentration are more likely to occur in samples with higher roughness. PL analysis at low temperature reveals in all samples a relatively slow (μs) red emission band related to deep bulk defects. The fast (sub-ns), surface-related blue PL band was observed in some samples. Blue PL disappeared after annealing in air at 500 °C. Room temperature Hall effect measurements confirm n-type conductivity, though with relatively low mobility, suggesting defect-related scattering. Persistent photoconductivity was observed under UV illumination, indicating deep trap states affecting charge transport. These results highlight the impact of deposition and post-treatment on polycrystalline ZnO thin films, offering insights into optimizing their performance for optoelectronic applications, such as UV detectors and transparent conductive oxides.https://www.mdpi.com/2079-4991/15/8/590ZnOoptical absorptancephotoluminescencesputteringHall effect
spellingShingle Zdeněk Remeš
Zdeněk Hubička
Pavel Hubík
Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
Nanomaterials
ZnO
optical absorptance
photoluminescence
sputtering
Hall effect
title Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
title_full Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
title_fullStr Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
title_full_unstemmed Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
title_short Optical and Transport Properties of ZnO Thin Films Prepared by Reactive Pulsed Mid-Frequency Sputtering Combined with RF ECWR Plasma
title_sort optical and transport properties of zno thin films prepared by reactive pulsed mid frequency sputtering combined with rf ecwr plasma
topic ZnO
optical absorptance
photoluminescence
sputtering
Hall effect
url https://www.mdpi.com/2079-4991/15/8/590
work_keys_str_mv AT zdenekremes opticalandtransportpropertiesofznothinfilmspreparedbyreactivepulsedmidfrequencysputteringcombinedwithrfecwrplasma
AT zdenekhubicka opticalandtransportpropertiesofznothinfilmspreparedbyreactivepulsedmidfrequencysputteringcombinedwithrfecwrplasma
AT pavelhubik opticalandtransportpropertiesofznothinfilmspreparedbyreactivepulsedmidfrequencysputteringcombinedwithrfecwrplasma