TY - JOUR
T1 - pH Controlled Nanostructure and Optical Properties of ZnO and Al-Doped ZnO Nanorod Arrays Grown by Microwave-Assisted Hydrothermal Method
T2 - https://doi.org/10.3390/nano12213735
AU - Al Farsi, Lamia M.
AU - Souier, Mohammed
AU - Al-Hinai, Muna H.
AU - Myint, Myo
AU - Htet Kyaw, Htet
AU - Widatallah, Hisham
AU - Al-Abri, Mohammed
N1 - Funding Information:
This research was funded by [Sultan Qaboos University] grant number [IG/SCI/PHYS/20/08].
Publisher Copyright:
© 2022 by the authors.
PY - 2022/10/24
Y1 - 2022/10/24
N2 - The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications.
AB - The low-temperature microwave-assisted hydrothermal method was used to successfully grow pure and Al-doped ZnO (AZO) nanorod (NR) arrays on glass substrates. The combined effects of doping and pH on the structural properties, surface chemistry, and optical properties of all samples were investigated. Thermodynamic-based simulations of the growth solution were performed and a growth mechanism, that considers the effects of both the pH and Al-doping, is proposed, and discussed. Tuning the solution pH is key parameter to grow well-aligned, single crystal, highly packed, and high aspect ratio nanorod arrays. Moreover, the optical absorption in the visible range is enhanced by controlling the pH value. The PL spectra reveal a shift of the main radiative emission from the band-to-band into a transition involving deep defect levels of Zinc interstitial Zni. This shift is caused by an enhancement of the non-radiative components (phonon relaxation) at high pH values. The production of well-ordered ZnO and AZO nanorod arrays with visible-active absorption/emission centers would increase their potential use in various applications.
KW - Al-doped zinc oxide
KW - crystal growth mechanism
KW - microwave-hydrothermal deposition
KW - nanostructure
KW - optical properties
KW - photoluminescence
KW - semiconductor
UR - https://www.mdpi.com/2079-4991/12/21/3735
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UR - https://www.mendeley.com/catalogue/847e9ca2-7cc5-3869-b27a-cf89688cab18/
U2 - 10.3390/nano12213735
DO - 10.3390/nano12213735
M3 - Article
C2 - 36364511
SN - 2079-4991
VL - 12
SP - 3735
JO - Nanomaterials
JF - Nanomaterials
IS - 21
M1 - 3735
ER -