Lead-Free Oxide Thin Films for Gas Detection

2013 ◽  
Vol 789 ◽  
pp. 105-111 ◽  
Author(s):  
Didier Fasquelle ◽  
S. Députier ◽  
M. Mascot ◽  
N. Uschanoff ◽  
V. Bouquet ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
First Generation ◽  
Sol Gel ◽  
Film Surface ◽  
Lead Free ◽  
Zno Films ◽  
First Year ◽  
Average Size ◽  
Different Gases

In view to develop gas sensors, a first generation of lead-free thin films was deposited by different techniques on commercial Si and Al2O3 substrates. During our research project, the correlation between the micro structure of films, the structure of the embedded sensors and the applied temperature range, is being studied. In the first year, doped and undoped BaTiO3, KNbO3 and ZnO thin films have been deposited by sol-gel and PLD techniques. BT and BST films have shown a polycrystalline structure with very fine and regular grains, while disoriented grains with an average size ranging from 50 to 200 nm were observed on the KNbO3 film surface, and ZnO films exhibited a columnar growth. All films were characterized and finally embedded to make semiconductor gas sensors which have been tested under different gases. In this first generation of sensors, ZnO sensors have shown encouraging preliminary results under CO and H2S gases. Keywords : thin films, lead-free oxide, sensor, gas.

scholarly journals On the Use of MOFs and ALD Layers as Nanomembranes for the Enhancement of Gas Sensors Selectivity

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1552 ◽  
Author(s):  
Weber ◽  
Graniel ◽  
Balme ◽  
Miele ◽  
Bechelany
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Metal Organic Frameworks ◽  
Atomic Layer ◽  
Operational Performance ◽  
Layer Deposition ◽  
Metal Organic ◽  
Further Development ◽  
Different Gases

Improving the selectivity of gas sensors is crucial for their further development. One effective route to enhance this key property of sensors is the use of selective nanomembrane materials. This work aims to present how metal-organic frameworks (MOFs) and thin films prepared by atomic layer deposition (ALD) can be applied as nanomembranes to separate different gases, and hence improve the selectivity of gas sensing devices. First, the fundamentals of the mechanisms and configuration of gas sensors will be given. A selected list of studies will then be presented to illustrate how MOFs and ALD materials can be implemented as nanomembranes and how they can be implemented to improve the operational performance of gas sensing devices. This review comprehensively shows the benefits of these novel selective nanomaterials and opens prospects for the sensing community.

Semiconducting Nano-structured SmFeO3-based Thin Films Prepared by Novel Sol-gel Method for Acetone Gas Sensors

2014 ◽  
Vol 152 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Ying Zhang ◽  
Qian-Qian Jia ◽  
Hui-Ming Ji ◽  
Jian-Jun Yu
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method

Composition Dependence of Crystallinity for Lead-Free (Li, Na, K)NbO3Powder and Thin Films Fabricated by Sol-Gel Process

2007 ◽  
Vol 358 (1) ◽  
pp. 175-180 ◽  
Author(s):  
Kiyotaka Tanaka ◽  
Ken-Ichi Kakimoto ◽  
Hitoshi Ohsato ◽  
Takashi Iijima
Keyword(s):  
Thin Films ◽  
Composition Dependence ◽  
Sol Gel ◽  
Lead Free ◽  
Sol Gel Process

Effects of Withdrawal Speeds on Properties of ZnO Thin Films Prepared by Sol-Gel Immerse Technique

2016 ◽  
Vol 680 ◽  
pp. 124-128 ◽  
Author(s):  
Chao Du ◽  
Yu Chun Zou ◽  
Zhi Qing Chen ◽  
Wen Kui Li ◽  
Shan Shan Luo
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Sol Gel ◽  
Wavelength Region ◽  
Zno Thin Films ◽  
Zno Films ◽  
Photoelectric Device ◽  
Near Ir ◽  
Crystal Film ◽  
Diffraction Peaks

ZnO thin films have attractive applications in photoelectric device, due to their excellent chemical, electrical and optical properties. In this paper, ZnO thin films with good c-axis preferred orientation and high transmittance are prepared on glass sheets by sol-gel immerse technique. The effects of withdrawal speeds on the growth process of thin film crystal, film crystal orientation and the crystallinity, the optical performance were investigated by XRD, SEM and UV-Vis spectrophotometry. The results show that the thin films were composed of better hexagonal wurtzite crystals with the c-axis prepared orientation. The transmittance of prepared thin films is over 80% in the visible-near IR region from 600 nm - 800 nm. ZnO films have sharp and narrow diffraction peaks, which indicates that the materials exhibit high crystallinity. With the withdrawal speeds increasing, the grain size of ZnO thin films and the intensity for all diffraction peaks were increased gradually. The growth model is changed from the stratified structure into the island structure in the growth process. The transmittance of the thin films decrease in the visible wavelength region, with the withdrawal speeds increasing.

scholarly journals Xerogels of Ammonium Polyvanadatomolybdate as Starting Material for Ammonia Gas Sensors

2015 ◽  
Vol 50 ◽  
pp. 71-79
Author(s):  
Vladimiras Bondarenka ◽  
R. Sereika ◽  
A. Mironas ◽  
S. Grebinskij
Keyword(s):  
Gas Sensors ◽  
Sol Gel ◽  
Soft Chemistry ◽  
Special Equipment ◽  
Ammonia Gas ◽  
Layer 4 ◽  
Ammonia Sensors ◽  
Sol Gel Synthesis ◽  
Ammonia Gas Sensors ◽  
Different Gases

The various gas sensors were designed for detection of different gases in the air using different oxides and impurities [1-3]. For example the manufacturing of ammonia sensors on the basis of CuxS-micro-porous-Si structure includes manufacture of micro-porous silicon, drawing on it of SiO2 isolating layer, and then the CuxS layer [4, 5]. The special equipment for all these processes is needed. More usable method for sensor production is so-called soft chemistry or sol–gel synthesis [6, 7].

scholarly journals Influence of the Sputtering Technique and Thermal Annealing on YSZ Thin Films for Oxygen Sensing Applications

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1165
Author(s):  
Emilio Paz Alpuche ◽  
Pascal Gröger ◽  
Xuetao Wang ◽  
Thomas Kroyer ◽  
Stefanos Fasoulas
Keyword(s):  
Thin Films ◽  
Gas Sensors ◽  
Electronic Conductivity ◽  
Film Surface ◽  
Annealing Treatment ◽  
Thin Film Surface ◽  
Sensing Applications ◽  
Partial Pressures ◽  
Sensor Current ◽  
Oxygen Gas

Yttria-stabilized zirconia (YSZ) thin films were deposited using direct current (reactive and metallic) and radio frequency magnetron sputtering. The effect of the deposition technique and annealing treatment on the microstructure and crystallinity of the thin films was assessed. Using the films produced in this work, oxygen gas sensors were built and their performance under vacuum conditions was evaluated. All the films exhibited a cubic crystalline structure after a post-deposition thermal treatment, regardless of the sputtering technique. When the annealing treatment surpassed 1000 °C, impurities were detected on the thin film surface. The oxygen gas sensors employing the reactive and oxide-sputtered YSZ thin films displayed a proportional increase in the sensor current as the oxygen partial pressure was increased in the evaluated pressure range (5 × 10−6 to 2 × 10−3 mbar). The sensors which employed the metallic-deposited YSZ films suffered from electronic conductivity at low partial pressures.

scholarly journals Enhanced Magnetic Properties of Co-Doped BiFeO3 Thin Films via Structural Progression

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1798
Author(s):  
Liang Bai ◽  
Mingjie Sun ◽  
Wenjing Ma ◽  
Jinghai Yang ◽  
Junkai Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Sol Gel ◽  
Sem Images ◽  
Size Mismatch ◽  
Structural Progression ◽  
Gel Technique ◽  
Average Size ◽  
Perovskite Lattice ◽  
Co Doped

Co3+ doping in BiFeO3 is expected to be an effective method for improving its magnetic properties. In this work, pristine BiFeO3 (BFO) and doped BiFe1-xCoxO3 (BFCxO, x = 0.01, 0.03, 0.05, 0.07 and 0.10) composite thin films were successfully synthesized by a sol–gel technique. XRD and Raman spectra indicate that the Co3+ ions are substituted for the Fe3+ ion sites in the BFO rhombohedral lattice. Raman vibration of oxygen octahedron is obviously weakened due to the lattice distortion induced by the size mismatch between two B-site cations (Fe3+ and Co3+ ions), which has an impact on the magnetic properties of BFCxO. SEM images reveal a denser agglomeration in Co-doped samples. TEM results indicate that the average size of grains is reduced due to the Co3+ substitution. XPS measurements illustrate that the replacement of Fe3+ with Co3+ effectively suppresses the generation of oxygen defects and increases the concentration of Fe3+ ions at the B-site of perovskite lattice. Vibrating sample magnetometer (VSM) measurements show that the remanent magnetization (Mr) of BFC0.07O (3.6 emu/cm3) and the saturation magnetization (Ms) of BFC0.10O (48.84 emu/cm3) thin film both increase by approximately two times at room temperature, compared with that of the pure BFO counterpart.

Resistive Switching Behaviour of Dip Coated ZnO Films with the Changing with Drawal Speed

2020 ◽  
Vol 978 ◽  
pp. 384-389
Author(s):  
Sritama Roy ◽  
Saswati Soumya Dash ◽  
Prasanna Kumar Sahu ◽  
Smita Mishra ◽  
Jyoti Prakash Kar
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Sol Gel ◽  
Dip Coating ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Thin Film Thickness ◽  
Withdrawal Speed ◽  
Current Voltage ◽  
P Type

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.

Studying on Preparation of AZO Thin Films with Sol-Gel Method

2010 ◽  
Vol 152-153 ◽  
pp. 868-873 ◽  
Author(s):  
Xiu Ling Lv ◽  
Yu Bo Dou ◽  
Juan Wang ◽  
Ying Xu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Sol Gel ◽  
Treatment Temperature ◽  
Zno Films ◽  
Gel Method ◽  
Sol Gel Method ◽  
Crystallization Properties ◽  
Doped Zno ◽  
Micro Morphology

Al doped ZnO thin films（AZO films） was prepared by sol-gel method. The influence of Parameters of different processes on the crystallization properties, micro-morphology and optical properties of this kind of films were studied, using by X-ray diffractometer, filed emission stereoscan, spectral photometer, hall admeasuring apparatus. The results indicated that the crystallization properties, micro-morphology and optical properties of Al doped ZnO films were best on the condition that the sol density was 0.5mol/L, hat treatment temperature is 600 and there is a 8-layer coating.

The Preparation of the Highly Preferred Orientation of AlN Thin Films on ZnO Substrates

2013 ◽  
Vol 669 ◽  
pp. 181-184
Author(s):  
Nan Ding ◽  
Li Ming Xu ◽  
Bao Jia Wu ◽  
Guang Rui Gu
Keyword(s):  
Thin Films ◽  
Film Surface ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Promising Candidate ◽  
Si Substrates ◽  
Good Crystallinity ◽  
Crystallite Structure

Zinc oxide (ZnO) films were prepared on Si substrates and then aluminum nitride (AlN) films were deposited on ZnO films by radio frequency (RF) magnetron sputtering. The crystal orientation, crystallite structure and surface morphology of AlN/ZnO films were characterized by X-ray diffraction (XRD), Raman spectrum and scanning electron microscopy (SEM). It was indicated that the AlN films were closely deposited on the ZnO film and had good crystallinity. Moreover, about 1μm-sized crystal particles with high c-axial orientation distributed uniformly on the AlN/ZnO film surface. It was indicated that ZnO could be a promising candidate as buffer layer for preparation of AlN thin films.

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