Electrochemical Synthesis of p-CuO Thin Films and Development of a p-CuO/n-ZnO Thin Film Hetero-Contact for Gas Sensing

<p>Pure and Zr doped ZnO thin films were prepared using SILAR technique. The influence of Zr doping on structural, morphological, optical and gas sensing properties of ZnO has been reported. X-ray diffraction study confirmed the formation of wurtzite structure of ZnO thin film (JCPDS 36-1451) fabricated by SILAR technique and the caluculated crystallites size of pure and doped ZnO were 39 and 36 nm respectively . SEM analysis of thin films has shown a completely different surface morphology. EDAX spetrum cnfirmed the presence of different compositional element in the fabriated thin films. Zr (3 wt%) doped ZnO thin film exhibited the best properties with a good transmittance and it has wide band gap of 3.26 eV. Photoluminescence emissions indicated increase in concentration of oxygen vacancies with introduction of dopant. NH3 vapour sensors were fabricated out of fabricated samples and it was observed that doped samples have significantly high sensing response, good selectivity, fast response and recovery time to ammonia vapoutr at room temperature.</p>

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Effects of Thermal Annealing on the Characteristics of High Frequency FBAR Devices

Coatings ◽

10.3390/coatings11040397 ◽

2021 ◽

Vol 11 (4) ◽

pp. 397

Author(s):

Yu-Chen Chang ◽

Ying-Chung Chen ◽

Bing-Rui Li ◽

Wei-Che Shih ◽

Jyun-Min Lin ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Thermal Annealing ◽

Electromechanical Coupling ◽

Zno Thin Films ◽

Electromechanical Coupling Coefficient ◽

Back Side ◽

Zno Thin Film ◽

Frequency Responses ◽

Sputtering System

In this study, piezoelectric zinc oxide (ZnO) thin film was deposited on the Pt/Ti/SiNx/Si substrate to construct the FBAR device. The Pt/Ti multilayers were deposited on SiNx/Si as the bottom electrode and the Al thin film was deposited on the ZnO piezoelectric layer as the top electrode by a DC sputtering system. The ZnO thin film was deposited onto the Pt thin film by a radio frequency (RF) magnetron sputtering system. The cavity on back side for acoustic reflection of the FBAR device was achieved by KOH solution and reactive ion etching (RIE) processes. The crystalline structures and surface morphologies of the films were analyzed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optimized as-deposited ZnO thin films with preferred (002)-orientation were obtained under the sputtering power of 80 W and sputtering pressure of 20 mTorr. The crystalline characteristics of ZnO thin films and the frequency responses of the FBAR devices can be improved by using the rapid thermal annealing (RTA) process. The optimized annealing temperature and annealing time are 400 °C and 10 min, respectively. Finally, the FBAR devices with structure of Al/ZnO/Pt/Ti/SiNx/Si were fabricated. The frequency responses showed that the return loss of the FBAR device with RTA annealing was improved from −24.07 to −34.66 dB, and the electromechanical coupling coefficient (kt2) was improved from 1.73% to 3.02% with the resonance frequency of around 3.4 GHz.

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Plasma Pre-Treatment of Polyethylene Terephthalate Substrate Influence on the Properties of ZnO Thin Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.895.41 ◽

2014 ◽

Vol 895 ◽

pp. 41-44

Author(s):

Seiw Yen Tho ◽

Kamarulazizi Ibrahim

Keyword(s):

Thin Film ◽

Thin Films ◽

Polyethylene Terephthalate ◽

Contact Angle Measurement ◽

Angle Measurement ◽

Zno Thin Films ◽

Zno Thin Film ◽

Water Contact ◽

Pre Treatment ◽

Pet Substrate

In this work, the influences of plasma pre-treatment on polyethylene terephthalate (PET) substrate to the properties of ZnO thin film have been carried out. ZnO thin films were successfully grown on PET substrate by spin coating method. In order to study the effects of plasma pre-treatment, a comparison of treated and untreated condition was employed. Water contact angle measurement had been carried out for PET wettability study prior to ZnO thin film coating. Morphology study of ZnO thin film was performed by scanning probe microscope (SPM). Besides, optical study of the ZnO thin film was done by using UV-vis spectrophotometer. All the measured results show that plasma pre-treatment of PET substrate plays an important role in enhancing the wettability of PET and optical properties of the ZnO thin films. In conclusion, pre-treatment of PET surface is essential to produce higher quality ZnO thin film on this particular substrate in which would pave the way for the integration of future devices.

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Effect of Temperature on the Electrical and Gas Sensing Properties of Polyaniline and Multiwall Carbon Nanotube Doped Polyaniline Composite Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.254.167 ◽

2011 ◽

Vol 254 ◽

pp. 167-170 ◽

Cited By ~ 1

Author(s):

Subodh Srivastava ◽

Sumit Kumar ◽

Vipin Kumar Jain ◽

Y.K. Vijay

Keyword(s):

Thin Film ◽

Thin Films ◽

Gas Sensing ◽

Hydrogen Gas ◽

Composite Thin Film ◽

Effect Of Temperature ◽

Multiwall Carbon Nanotube ◽

Film Sensor ◽

Composite Thin Films ◽

Pani Composite

In the present work we have reported the effect of temperature on the gas sensing properties of pure Polyaniline (PANI) and Multiwall carbon nanotube (MWNT) doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and MWNT doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline using ammonium persulfate in an acidic medium. The thin sensing film of chemically synthesized PANI and MWNT doped PANI composite were deposited onto finger type Cu-interdigited electrodes using spin cast technique to prepared chemiresistor type gas sensor. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature, MWNT doped PANI composite sensor shows higher response value and sensitivity with good repeatability in comparison to pure PANI thin film sensor. It was also observed that both PANI and MWNT doped PANI composite thin film based sensors showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

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NO2 Gas Sensing Mechanism of ZnO Thin-Film Transducers: Physical Experiment and Theoretical Correlation Study

ACS Sensors ◽

10.1021/acssensors.6b00051 ◽

2016 ◽

Vol 1 (4) ◽

pp. 406-412 ◽

Cited By ~ 42

Author(s):

Athanasios Tamvakos ◽

Kiprono Korir ◽

Dimitrios Tamvakos ◽

Davide Calestani ◽

Giancarlo Cicero ◽

...

Keyword(s):

Thin Film ◽

Gas Sensing ◽

Correlation Study ◽

Physical Experiment ◽

Zno Thin Film ◽

Sensing Mechanism

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Enhanced UV Photon-response of Tin Nano Cluster Loaded- laser Irradiated ZnO Thin film detector

MRS Proceedings ◽

10.1557/opl.2011.206 ◽

2011 ◽

Vol 1288 ◽

Author(s):

Rashmi Menon ◽

K. Sreenivas ◽

Vinay Gupta

Keyword(s):

Thin Film ◽

Thin Films ◽

Magnetron Sputtering ◽

Surface States ◽

Response Speed ◽

Rf Magnetron Sputtering ◽

Fast Response ◽

Zno Thin Films ◽

Zno Thin Film ◽

Photo Response

ABSTRACTZinc Oxide (ZnO), II-VI compound semiconductor, is a promising material for ultraviolet (UV) photon sensor applications due to its attractive properties such as good photoconductivity, ease processing at low temperatures and excellent radiation hardness. The rf magnetron sputtering is a suitable deposition technique due to better control over stoichiometry and deposition of uniform film. Studies have shown that the presence of surface defects in ZnO and subsequently their passivation are crucial for enhanced photo-response characteristics, and to obtain the fast response speed. Worldwide efforts are continuing to develop good quality ZnO thin films with novel design structures for realization of an efficient UV photon sensor. In the present work, UV photon sensor is fabricated using a ZnO thin films deposited by rf magnetron sputtering on the corning glass substrate. Photo-response, (Ion/Ioff) of as-grown ZnO film of thickness 100 nm is found to be 3×103 with response time of 90 ms for UV intensity of 140 μW/cm2 (λ = 365 nm). With irradiation on ZnO thin film by pulsed Nd:YAG laser (forth harmonics 266 nm), the sensitivity of the UV sensor is found to enhance. The photo-response increases after laser irradiation to 4x104 with a fast response speed of 35 ms and attributed to the change in surface states and the native defects in the ZnO thin film. Further, enhancement in the ultraviolet (UV) photo-response (8×104) of detector was observed after integrating the nano-scale islands of Sn metal on the surface of laser irradiated ZnO thin film.

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ELECTRICAL AND OPTICAL PROPERTIES OF ZnO THIN FILMS PREPARED BY R.F. MAGNETRON SPUTTERING

International Journal of Modern Physics B ◽

10.1142/s0217979211100357 ◽

2011 ◽

Vol 25 (20) ◽

pp. 2741-2749 ◽

Cited By ~ 3

Author(s):

J. C. ZHOU ◽

L. LI ◽

L. Y. RONG ◽

B. X. ZHAO ◽

Y. M. CHEN ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Optical Properties ◽

Magnetron Sputtering ◽

Oxide Thin Film ◽

Zno Thin Films ◽

Zno Thin Film ◽

Electrical And Optical Properties ◽

Axis Orientation ◽

Sputtering Power

High transparency and conductivity of transparent conducting oxide thin film are very important for improving the efficiency of solar cells. ZnO thin film is a better candidate for transparent conductive layer of solar cell. N-type ZnO thin films were prepared by radio-frequency magnetron sputtering on glass substrates. ZnO thin films underwent annealing treatment after deposition. The influence of the sputtering power on the surface morphology, the electrical and optical properties were studied by AFM, XRD, UV2450 and HMS-3000. The experimental results indicate that the crystal quality of ZnO thin film is improved and all films show higher c-axis orientation with increasing sputtering power from 50 to 125 W. The average transparency of ZnO thin films is higher than 90% in the range of 400–900 nm between the sputtering power of 50–100 W. After the rapid thermal annealing at 550°C for 300 s under N2 ambient, the minimum resistivity reach to 10-2Ω⋅ cm .

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