Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films

Undoped ZnO, Gd-doped ZnO with various doping concentration (1, 3, 5, and 7 at%), and 3 at% (Gd, Al) co-doped ZnO films were prepared on a glass substrate using the co-reactive sputtering method. The influence of the doping and co-doping process on the films was characterized using X-ray diffraction...

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Main Authors: Nur Amaliyana Raship, Siti Nooraya Mohd Tawil, Nafarizal Nayan, Khadijah Ismail, Anis Suhaili Bakri, Zulkifli Azman, Faezahana Mohkhter
Format: Article
Language:English
Published: MDPI AG 2022-11-01
Series:Materials
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Online Access:https://www.mdpi.com/1996-1944/15/22/8025
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author Nur Amaliyana Raship
Siti Nooraya Mohd Tawil
Nafarizal Nayan
Khadijah Ismail
Anis Suhaili Bakri
Zulkifli Azman
Faezahana Mohkhter
author_facet Nur Amaliyana Raship
Siti Nooraya Mohd Tawil
Nafarizal Nayan
Khadijah Ismail
Anis Suhaili Bakri
Zulkifli Azman
Faezahana Mohkhter
author_sort Nur Amaliyana Raship
collection DOAJ
description Undoped ZnO, Gd-doped ZnO with various doping concentration (1, 3, 5, and 7 at%), and 3 at% (Gd, Al) co-doped ZnO films were prepared on a glass substrate using the co-reactive sputtering method. The influence of the doping and co-doping process on the films was characterized using X-ray diffraction, FESEM, EDX, MFM, VSM, UV–VIS spectroscopy, and the Hall Effect measurement at room temperature. XRD study confirmed that the Gd and Al ions are incorporated into a ZnO lattice. EDX analysis confirmed the existence of Zn, O, Al, and Gd elements in the prepared Gd-doped ZnO and (Gd, Al) co-doped ZnO films, which suggests the successful doping procedure. All the deposited films obtained maximum optical transmittance above 80%, showing a high transparency of the films in the visible region. The optical band gap was found red-shifted from 3.11 to 3.21 eV with the increase in Gd doping concentration. The increase in band gap energy from 3.14 eV to 3.16 eV was obtained for 3 at% Gd and 3 at% (Gd, Al) co-doped ZnO films. The MFM measurement proved the existence of room-temperature ferromagnetism and spin polarization in Gd and (Gd, Al) co-doped ZnO films. By co-doping with Al, the result obtained from MFM shows the enhancement of magnetic properties, as it exhibited a smaller domain size with a shorter magnetic correlation length <i>L</i>, a larger phase shift Φ<sub>rms</sub>, and the highest value of <i>δf</i><sub>rms</sub> compared to the sample with 3 at% Gd incorporated into ZnO. The carrier concentration and electrical conductivity increased with the increase in Gd concentration, whereas the electrical resistivity and hall mobility showed a reverse trend. The similar trend of results obtained for 3 at% (Gd, Al) co-doped ZnO as compared to 3 at% Gd-doped ZnO also indicates greater electrical properties after a shallow donor such as aluminum was incorporated into Gd-doped ZnO thin films. In conclusion, for future applications, one should consider the possible influence of other types of shallow donor incorporation in an attempt to enhance the properties of new types of diluted magnetic semiconductors (DMSs).
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spelling doaj.art-8d489b8646ef4bf090a1af6dcec1f19e2023-11-24T09:02:56ZengMDPI AGMaterials1996-19442022-11-011522802510.3390/ma15228025Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin FilmsNur Amaliyana Raship0Siti Nooraya Mohd Tawil1Nafarizal Nayan2Khadijah Ismail3Anis Suhaili Bakri4Zulkifli Azman5Faezahana Mohkhter6Department of Electrical and Electronic Engineering, Universiti Pertahanan Nasional Malaysia (UPNM), Kem Sungai Besi, Kuala Lumpur 57000, MalaysiaDepartment of Electrical and Electronic Engineering, Universiti Pertahanan Nasional Malaysia (UPNM), Kem Sungai Besi, Kuala Lumpur 57000, MalaysiaMicroelectronic and Nanotechnology-Shamsuddin Research Centre (MiNT-SRC), Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja 86400, MalaysiaDepartment of Electrical and Electronic Engineering, Universiti Pertahanan Nasional Malaysia (UPNM), Kem Sungai Besi, Kuala Lumpur 57000, MalaysiaFaculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja 86400, MalaysiaFaculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja 86400, MalaysiaMicroelectronic and Nanotechnology-Shamsuddin Research Centre (MiNT-SRC), Universiti Tun Hussein Onn Malaysia (UTHM), Parit Raja 86400, MalaysiaUndoped ZnO, Gd-doped ZnO with various doping concentration (1, 3, 5, and 7 at%), and 3 at% (Gd, Al) co-doped ZnO films were prepared on a glass substrate using the co-reactive sputtering method. The influence of the doping and co-doping process on the films was characterized using X-ray diffraction, FESEM, EDX, MFM, VSM, UV–VIS spectroscopy, and the Hall Effect measurement at room temperature. XRD study confirmed that the Gd and Al ions are incorporated into a ZnO lattice. EDX analysis confirmed the existence of Zn, O, Al, and Gd elements in the prepared Gd-doped ZnO and (Gd, Al) co-doped ZnO films, which suggests the successful doping procedure. All the deposited films obtained maximum optical transmittance above 80%, showing a high transparency of the films in the visible region. The optical band gap was found red-shifted from 3.11 to 3.21 eV with the increase in Gd doping concentration. The increase in band gap energy from 3.14 eV to 3.16 eV was obtained for 3 at% Gd and 3 at% (Gd, Al) co-doped ZnO films. The MFM measurement proved the existence of room-temperature ferromagnetism and spin polarization in Gd and (Gd, Al) co-doped ZnO films. By co-doping with Al, the result obtained from MFM shows the enhancement of magnetic properties, as it exhibited a smaller domain size with a shorter magnetic correlation length <i>L</i>, a larger phase shift Φ<sub>rms</sub>, and the highest value of <i>δf</i><sub>rms</sub> compared to the sample with 3 at% Gd incorporated into ZnO. The carrier concentration and electrical conductivity increased with the increase in Gd concentration, whereas the electrical resistivity and hall mobility showed a reverse trend. The similar trend of results obtained for 3 at% (Gd, Al) co-doped ZnO as compared to 3 at% Gd-doped ZnO also indicates greater electrical properties after a shallow donor such as aluminum was incorporated into Gd-doped ZnO thin films. In conclusion, for future applications, one should consider the possible influence of other types of shallow donor incorporation in an attempt to enhance the properties of new types of diluted magnetic semiconductors (DMSs).https://www.mdpi.com/1996-1944/15/22/8025Gd-doped ZnOshallow donormagnetic force microscopyco-dopingsputtering
spellingShingle Nur Amaliyana Raship
Siti Nooraya Mohd Tawil
Nafarizal Nayan
Khadijah Ismail
Anis Suhaili Bakri
Zulkifli Azman
Faezahana Mohkhter
Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
Materials
Gd-doped ZnO
shallow donor
magnetic force microscopy
co-doping
sputtering
title Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
title_full Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
title_fullStr Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
title_full_unstemmed Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
title_short Magnetic Domain Characterization and Physical Properties of Gd-Doped and (Gd, Al) Co-Doped ZnO Thin Films
title_sort magnetic domain characterization and physical properties of gd doped and gd al co doped zno thin films
topic Gd-doped ZnO
shallow donor
magnetic force microscopy
co-doping
sputtering
url https://www.mdpi.com/1996-1944/15/22/8025
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