Reactive sputtered ZnO thin films: Influence of the O2/Ar flow ratio on the oxygen vacancies and paramagnetic active sites

Camacho-Berríos, Adrián A.; Pantojas, V.; Otaño, Wilfredo

doi:10.1016/j.tsf.2019.137641

Cited by 30 publications

(10 citation statements)

References 39 publications

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“…In fact in this poisoning phenomenon gives rise to two effects, (1) limiting the arrival rate of Zr atoms on the substrate and (2) decreasing the acceleration of Ar + ions toward the target, thus decreasing the sputtering yield. [ 66,67 ] Lewis et al. [ 68 ] observed similar behavior for reactively sputtered TiN coatings.…”

Section: Resultsmentioning

confidence: 75%

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Azibi

Saoula

Madaoui

et al. 2021

Crystal Research and Technology

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Zirconium nitride films are deposited onto stainless steel AISI 316L and silicon (100) by radio frequency magnetron sputtering at different nitrogen flow ratios [N2/(Ar+N2)] varied between 0 and 0.25). Scanning electron microscope, atomic force microscopy, X‐ray diffraction (XRD), and Raman are used to investigate the surface morphology and microstructure of the thin films. The mechanical and electrochemical properties of all coatings are evaluated and compared with the uncoated AISI 316L to explore the efficiency of surface modification. The XRD and Raman analysis show that all the films are crystalline. This shows that the increased nitrogen content leads to a transformation from hexagonal α‐Zr phase to cubic c‐Zr and then to mixed α‐Zr and face centered cubic c‐ZrN phases. The films deposited with nitrogen flow ratio of 0.2 show the highest hardness of 32.2 GPa. Using the potentiodynamic polarization method, the corrosion behavior of the films is studied in Hank's solution. The comparison between uncoated and coated substrates shows a decrease in corrosion current density for all coated samples.

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Section: Resultsmentioning

confidence: 75%

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Azibi

Saoula

Madaoui

et al. 2021

Crystal Research and Technology

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“…Since oxygen vacancies are recognized as a crucial factor in gas reactions, many researchers have studied the effects of deposition parameters , and annealing conditions on oxygen vacancies and analyzed the characteristics of different defect positions. , However, there has been little interest in hydroxy groups compared to interest in oxygen vacancy. Surface hydroxy groups have been observed in other MOXs, such as SnO 2 , ZnO, and TiO 2 . Therefore, it is desirable to study how hydroxy groups affect the gas reaction in MOX sensors.…”

Section: Discussionmentioning

confidence: 99%

“…32,33 However, there has been little interest in hydroxy groups compared to interest in oxygen vacancy. Surface hydroxy groups have been observed in other MOXs, such as SnO 2 , 30 ZnO, 31 and TiO 2 . 67 Therefore, it is desirable to study how hydroxy groups affect the gas reaction in MOX sensors.…”

Section: ■ Conclusionmentioning

confidence: 97%

Transducer-Aware Hydroxy-Rich-Surface Indium Oxide Gas Sensor for Low-Power and High-Sensitivity NO₂ Gas Sensing

Jung

Shin

Jeon

et al. 2023

ACS Appl. Mater. Interfaces

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Low-power metal oxide (MOX)-based gas sensors are widely applied in edge devices. To reduce power consumption, nanostructured MOXbased sensors that detect gas at low temperatures have been reported. However, the fabrication process of these sensors is difficult for mass production, and these sensors are lack uniformity and reliability. On the other hand, MOX film-based gas sensors have been commercialized but operate at high temperatures and exhibit low sensitivity. Herein, commercially advantageous highly sensitive, film-based indium oxide sensors operating at low temperatures are reported. Ar and O 2 gases are simultaneously injected during the sputtering process to form a hydroxy-richsurface In 2 O 3 film. Conventional indium oxide (In 2 O 3 ) films (A0) and hydroxy-rich indium oxide films (A1) are compared using several analytical techniques. A1 exhibits a work function of 4.92 eV, larger than that of A0 (4.42 eV). A1 exhibits a Debye length 3.7 times longer than that of A0. A1 is advantageous for gas sensing when using field effect transistors (FETs) and resistors as transducers. Because of the hydroxy groups present on the surface of A1, A1 can react with NO 2 gas at a lower temperature (∼100 °C) than A0 (180 °C). Operando diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) shows that NO 2 gas is adsorbed to A1 as nitrite (NO 2 − ) at 100 °C and nitrite and nitrate (NO 3 − ) at 200 °C. After NO 2 is adsorbed as nitrate, the sensitivity of the A1 sensor decreases and its low-temperature operability is compromised. On the other hand, when NO 2 is adsorbed only as nitrite, the performance of the sensor is maintained. The reliable hydroxy-rich FET-type gas sensor shows the best performance compared to that of the existing film-based NO 2 gas sensors, with a 2460% response to 500 ppb NO 2 gas at a power consumption of 1.03 mW.

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“…The crystallinity and oxygen content of reactively sputtered ZnO film was found to be largely controlled by the O 2 /Ar ratio during sputtering. Further, it influences the oxygen vacancy (V O ) formations during the electroforming of conductive filaments [ 7 ]. Jing et al and Gu et al, have explained the mechanism [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Improved Resistive Switching with Low-Power Synaptic Behaviors of ZnO/Al2O3 Bilayer Structure

et al. 2022

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In this work, the resistive switching behavior of bilayer ZnO/Al2O3-based resistive-switching random access memory (RRAM) devices is demonstrated. The polycrystalline nature of the ZnO layer confirms the grain boundary, which helps easy oxygen ion diffusion. Multilevel resistance states were modulated under DC bias by varying the current compliance from 0.1 mA to 0.8 mA, the SET operations where the low resistance state of the memristor device was reduced from 25 kΩ to 2.4 kΩ. The presence of Al2O3 acts as a redox layer and facilitates oxygen vacancy exchange that demonstrates stable gradual conductance change. Stepwise disruption of conductive filaments was monitored depending on the slow DC voltage sweep rate. This is attributed to the atomic scale modulation of oxygen vacancies with four distinct reproducible quantized conductance states, which shows multilevel data storage capability. Moreover, several crucial synaptic properties such as potentiation/depression under identical presynaptic pulses and the spike-rate-dependent plasticity were implemented on ITO/ZnO/Al2O3/TaN memristor. The postsynaptic current change was monitored defining the long-term potentiation by increasing the presynaptic stimulus frequency from 5 Hz to 100 Hz. Moreover, the repetitive pulse voltage stimulation transformed the short-term plasticity to long-term plasticity during spike-number-dependent plasticity.

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Reactive sputtered ZnO thin films: Influence of the O2/Ar flow ratio on the oxygen vacancies and paramagnetic active sites

Cited by 30 publications

References 39 publications

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Transducer-Aware Hydroxy-Rich-Surface Indium Oxide Gas Sensor for Low-Power and High-Sensitivity NO₂ Gas Sensing

Improved Resistive Switching with Low-Power Synaptic Behaviors of ZnO/Al2O3 Bilayer Structure

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Reactive sputtered ZnO thin films: Influence of the O2/Ar flow ratio on the oxygen vacancies and paramagnetic active sites

Cited by 30 publications

References 39 publications

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Effects of Nitrogen Content on the Structural, Mechanical, and Corrosion Properties of ZrN Thin Films Grown on AISI 316L by Radiofrequency Magnetron Sputtering

Transducer-Aware Hydroxy-Rich-Surface Indium Oxide Gas Sensor for Low-Power and High-Sensitivity NO2 Gas Sensing

Improved Resistive Switching with Low-Power Synaptic Behaviors of ZnO/Al2O3 Bilayer Structure

Contact Info

Product

Resources

About

Transducer-Aware Hydroxy-Rich-Surface Indium Oxide Gas Sensor for Low-Power and High-Sensitivity NO₂ Gas Sensing