scholarly journals Using Different Ions in the Hydrothermal Method to Enhance the Photoluminescence Properties of Synthesized ZnO-Based Nanowires

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 446 ◽  
Author(s):  
Ya-Fen Wei ◽  
Wen-Yaw Chung ◽  
Cheng-Fu Yang ◽  
Jei-Ru Shen ◽  
Chih-Cheng Chen
Keyword(s):  
Hydrothermal Process ◽  
Zno Nanowires ◽  
Zno Films ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Doped Zno ◽  
Xrd Patterns ◽  
Surface Morphologies ◽  
The Eu

ZnO films with a thickness of ~200 nm were deposited on SiO2/Si substrates as the seed layer. Then Zn(NO3)2-6H2O and C6H12N4 containing different concentrations of Eu(NO3)2-6H2O or In(NO3)2-6H2O were used as precursors, and a hydrothermal process was used to synthesize pure ZnO as well as Eu-doped and In-doped ZnO nanowires at different synthesis temperatures. X-ray diffraction (XRD) was used to analyze the crystallization properties of the pure ZnO and the Eu-doped and In-doped ZnO nanowires, and field emission scanning electronic microscopy (FESEM) was used to analyze their surface morphologies. The important novelty in our approach is that the ZnO-based nanowires with different concentrations of Eu3+ and In3+ ions could be easily synthesized using a hydrothermal process. In addition, the effect of different concentrations of Eu3+ and In3+ ions on the physical and optical properties of ZnO-based nanowires was well investigated. FESEM observations found that the undoped ZnO nanowires could be grown at 100 °C. The third novelty is that we could synthesize the Eu-doped and In-doped ZnO nanowires at temperatures lower than 100 °C. The temperatures required to grow the Eu-doped and In-doped ZnO nanowires decreased with increasing concentrations of Eu3+ and In3+ ions. XRD patterns showed that with the addition of Eu3+ (In3+), the diffraction intensity of the (002) peak slightly increased with the concentration of Eu3+ (In3+) ions and reached a maximum at 3 (0.4) at%. We show that the concentrations of Eu3+ and In3+ ions have considerable effects on the synthesis temperatures and photoluminescence properties of Eu3+-doped and In3+-doped ZnO nanowires.

A Novel Synthesis of CaWO4:Eu3+ Flower Like Microcrystals in Ethanol/Water Mixed System and Characterization

2012 ◽  
Vol 531-532 ◽  
pp. 512-518 ◽  
Author(s):  
Ye Qing Chen ◽  
Joo Hyun Lee ◽  
Sung Wook Park ◽  
Byung Kee Moon ◽  
Byung Chun Choi ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hydrothermal Process ◽  
Volume Ratio ◽  
Mixed System ◽  
Mixed Solution ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Xrd Patterns

In this paper, we report a successful synthesis of CaWO4:Eu3+ phosphor via an ethanol assisted hydrothermal process. X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM) were used to investigate the growth of the products. The water and ethanol volume ratio is found to have extraordinary effect on the particle size and morphological appearance. Flower like ~ 1µm superstructures can be obtained with mixed solution of w/e of 50/50 at 120 °C hydrothermal sysnthesis for 12 h. High concentration of ethanol in aqueous solution was discovered to have a tendency in limiting the interaction between the small particles for crystallization. Temperature and time experiments were also performed to further investigate the growth mechanism of the ethanol assisted hydrothermal process. The photoluminescence properties of flower like CaWO4:Eu3+ has also been investigated.

Properties of ZnO Thin Films Grown on Si Substrates by Ultrasonic Spray and ZnO/Si Heterojunctions

2009 ◽  
Vol 609 ◽  
pp. 133-137 ◽  
Author(s):  
N. Zebbar ◽  
M.S. Aida ◽  
A.E.K. Hafdallah ◽  
O. Daranfad ◽  
H. Lekiket ◽  
...  
Keyword(s):  
Zno Films ◽  
X Ray Diffraction ◽  
Small Current ◽  
Si Substrates ◽  
Ultrasonic Spray ◽  
Spray Method ◽  
Current Voltage ◽  
Maximum Conductivity ◽  
Doped Zno ◽  
Substrate Temperatures

Experimental analysis of current –voltage and capacitance-voltage characteristics of n-ZnO/p-Si (100) heterostructures were presented. Undoped and In-doped ZnO films were deposited by the simple ultrasonic spray method on p-Si substrates (100) at varied substrate temperatures from 200 to 400°C. The structural and optical properties of ZnO films were investigated using X-ray diffraction (XRD) and transmission spectra respectively. The electrical conductivity is calculated from transport measurement in a two probes coplanar structure. It is found that the doped ZnO: In films have higher (002) diffraction peak than undoped ZnO. All films exhibit a high transparency about 85%. The maximum conductivity is observed at 350°C for doped films but increases with substrate temperature for undoped ones. Current–voltage (I-V) characteristics of all n-ZnO/p-Si heterojunctions exhibit non linear characteristics with a small current leakage in the reverse voltage. The obtained device shows a barrier height in the order of 0.65 eV, this is consistent with the theoretical value 0.67eV. The capacitance increases with increasing reverse bias in an approximately linear 1/C2-V relationship.

scholarly journals Investigation of the Optimal Parameters in Hydrothermal Method for the Synthesis of ZnO Nanorods

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ying-Chung Chen ◽  
Huan-Yi Cheng ◽  
Cheng-Fu Yang ◽  
Yuan-Tai Hsieh
Keyword(s):  
Deposition Time ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Second Step ◽  
Zno Films ◽  
Optimal Parameters ◽  
X Ray Diffraction ◽  
Step Method ◽  
Si Substrates ◽  
The Face

We investigated a two-step method to deposit the ZnO-based nanostructure films, including nanorods and nanoflowers. In the first step, sputtering method was used to deposit the ZnO films on SiO2/Si substrates as the seed layer. In the second step, Zn(NO3)2–6H2O and C6H12N4were used as precursors and hydrothermal process was used as the method to synthesize the ZnO films. After that, the ZnO films were measured by an X-ray diffraction pattern and a FESEM to analyze their crystallization and morphology. We had found that the ZnO films had three different morphologies synthesized on ZnO/SiO2/Si substrates, including irregular-plate structure films, nanorod films, and beautiful chrysanthemum-like clusters (nanoflower films). We would prove that the face direction of ZnO/SiO2/Si substrates in the hydrothermal bottle and deposition time were two important factors to influence the synthesized results of the ZnO films.

P-Doped p-Type ZnΟ Films Deposited by Sputtering and Diffusing

2012 ◽  
Vol 557-559 ◽  
pp. 1984-1987
Author(s):  
Hui Qun Zhu ◽  
Yu Ming Li ◽  
Jun Long Li ◽  
Ling Sun
Keyword(s):  
Hole Concentration ◽  
Hall Effect Measurement ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
Phosphorus Concentration ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Measurement Results ◽  
Doped Zno ◽  
P Type

P-doped ZnO thin films were prepared on different Si substrates by RF magnetron sputtering in Ar and O2 mixed atmosphere. The P-doped ZnO films were changed from n-type to p-type by phosphorus diffusing from the n-Si substrates with higher phosphorus concentration into the ZnO films during depositing. The crystal structure of the ZnO films was examined by X-ray diffraction and confirmed to belong to wurtzite and highly c-axis oriented primarily perpendicular to the substrate. The Hall effect measurement results show that the corresponding hole concentration and risistivity of the P-doped ZnO film was 8.982×1017 cm-3 and 1.489 Ω•cm respectively. This reveals that the P-doped ZnO thin film is really p-type behavior.

STUDY ON PHOTOLUMINESCENCE PROPERTIES OF Co-DOPED ZnO

2014 ◽  
Vol 28 (09) ◽  
pp. 1450033 ◽  
Author(s):  
SHUXIA GUO ◽  
JIWU LI ◽  
ZULIANG DU
Keyword(s):  
Blue Emission ◽  
Green Emission ◽  
Blue Shift ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Charge Transfer Transitions ◽  
Doped Zno ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Co Doped

ZnO and Co -doped ZnO have been synthesized by co-precipitation technique. X-ray diffraction (XRD) patterns and absorption spectra show that Co ions are doped into the lattice positions of ZnO . Photoluminescence (PL) experiments on the samples have been performed in order to study the sp–d interaction in ZnO : Co . Room temperature measurements show two additional emissions related to Co besides the ZnO exciton-related and trap emissions. The two emissions are attributed to the transitions from Co + to the excited Co 2+ state and from 2 E(G) to 4 A 2 (F) , respectively. The charge-transfer transitions related to Co 2+ exciting 3d intrashell luminescence at 1.78 eV has been observed. A blue-shift in the exciton-related emission, a red-shift in the blue emission and no shift in the green emission were revealed and interpreted by the sp–d interaction.

scholarly journals Photocatalytic Performance of ZnO: Al Films under Different Light Sources

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Pradhan ◽  
Juan Carlos Alonso ◽  
Monserrat Bizarro
Keyword(s):  
White Light ◽  
Irradiation Time ◽  
Zno Films ◽  
Light Sources ◽  
X Ray Diffraction ◽  
Treatment Processes ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Very High ◽  
High Degradation Rate

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.

Effects of Indium Incorporation on the Optical Properties of ZnO Films

2006 ◽  
Vol 11-12 ◽  
pp. 159-162 ◽  
Author(s):  
Yong Ge Cao ◽  
Lei Miao ◽  
Sakae Tanemura ◽  
Yasuhiko Hayashi ◽  
Masaki Tanemura
Keyword(s):  
Optical Transmission ◽  
Full Width Half Maximum ◽  
Structural Disorder ◽  
Band Gaps ◽  
Zno Films ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optical Band Gaps ◽  
Xrd Patterns

Transparent indium-doped ZnO (IZO) films with low In content (<6at%) were fabricated through radio-frequency (rf) helicon magnetron sputtering. Formation of In-Zn-O solid solution was confirmed by X-ray diffraction (XRD) patterns. Incorporation of indium into ZnO films enhances the optical transmission in the visible wavelength. The optical band-gaps slightly increase from 3.25eV (ZnO) to 3.28eV (In0.04Zn0.96O) and to 3.30eV (In0.06Zn0.94O) due to Burstain-Moss effect. The Urbach tail parameter E0, which is believed to be a function of structural disorder, increases from 79meV (ZnO), to 146meV (In0.04Zn0.96O), and to 173meV (In0.06Zn0.94O), which is consistent with increase of Full-Width Half-Maximum (FWHM) in corresponding XRD patterns. Decreasing in crystal quality with increasing indium concentration is also confirmed by photoluminescence spectra.

Sign in / Sign up

Export Citation Format

Share Document