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111.
M.H. Mamat Z. KhusaimiM.Z. Musa M.F. Malek M. Rusop 《Sensors and actuators. A, Physical》2011,171(2):241-247
Unique and novel thin films with aluminium (Al)-doped zinc oxide (ZnO) nanostructures consisting of nanorod-nanoflake networks were prepared for metal-semiconductor-metal (MSM)-type ultraviolet (UV) photoconductive sensor applications. These nanostructures were grown on a glass substrate coated with a seed layer using a combination of ultrasonic-assisted sol-gel and immersion methods. The synthesised ZnO nanorods had diameters varying from 10 to 40 nm. Very thin nanoflake structures were grown vertically and horizontally on top of the nanorod array. The thin film had good ZnO crystallinity with a root mean square roughness of approximately 13.59 nm. The photocurrent properties for the Al-doped ZnO nanorod-nanoflake thin films were more than 1.5 times greater than those of the seed layer when the sensor was illuminated with 365 nm UV light at a density of 5 mA/cm2. The responsivity of the device was found to be dependent on the bias voltage. We found that similar photocurrent curves were produced over eight cycles, which indicated that the UV sensing capability of the fabricated sensor was highly reproducible. Our results provide a new approach for utilising the novel structure of Al-doped ZnO thin films with a nanorod-nanoflake network for UV sensor applications. To the best of our knowledge, UV photoconductive sensors using Al-doped ZnO thin films with a nanorod-nanoflake network have not yet been reported. 相似文献
112.
T. LalinskýAuthor VitaeG. VankoAuthor Vitae M. ValloAuthor Vitae M. Dr?íkAuthor VitaeJ. BrunckoAuthor Vitae J. JakovenkoAuthor VitaeV. KutišAuthor Vitae I. RýgerAuthor VitaeŠ. Haš?íkAuthor Vitae M. HusákAuthor Vitae 《Sensors and actuators. A, Physical》2011,172(2):386-391
We report on a piezoelectric response investigation of AlGaN/GaN circular high electron mobility transistor (C-HEMT) based ring gate capacitor as a new stress sensor device to be potentially applied for dynamic high-pressure sensing. A ring gate capacitor of C-HEMT with an additional ZnO gate interfacial layer was used to measure the changes in the piezoelectric charge induced directly by the variation of piezoelectric polarization of both gate piezoelectric layers (AlGaN, ZnO) for harmonic loading at different excitation frequences. Our experimental results show that about 10 nm thick piezoelectric ZnO layer grown on ring gate/AlGaN interface of C-HEMT can yield almost a 60% increase in the piezoelectric detection sensitivity of the device due to its higher piezoelectric coefficient. A three-dimensional CoventorWare simulation is carried out to confirm the increase in the measured piezoelectric response of ZnO based ring gate capacitor of C-HEMT. 相似文献
113.
Kyung Min ByunAuthor VitaeNak-Hyeon KimAuthor Vitae Yeong Hwan KoAuthor VitaeJae Su YuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(1):375-379
We demonstrated an enhanced surface plasmon resonance detection incorporating ZnO nanorod arrays (NRAs) built on a thin gold film. ZnO NRAs were fabricated by wet chemical growth method and used for the detection of DNA hybridization. Experimental results exhibited that ZnO NRAs provided a notable sensitivity improvement by more than 3 times, which is attributed to an increase in the surface reaction area. The measured sensitivity enhancement matched well with the numerical analyses based on the effective medium theory. Our approach is intended to show the feasibility and extend the applicability of the ZnO-based SPR biosensor to diverse biomolecular binding events. 相似文献
114.
Kang-Min KimAuthor VitaeHae-Ryong KimAuthor Vitae Kwon-Il ChoiAuthor VitaeHyo-Joong KimAuthor Vitae Jong-Heun LeeAuthor Vitae 《Sensors and actuators. B, Chemical》2011,155(2):745-751
Highly crystalline ZnO hierarchical nanostructures were prepared at room temperature through the alkaline hydrolysis of zinc salt by the forced mixing of two immiscible solutions: Zn-nitrate aqueous solution and oleic-acid-dissolved n-hexane solution. The oleic acid acted as a surfactant in the room-temperature formation of well-defined ZnO hierarchical nanostructures, which subsequently demonstrated a sensitive and selective detection of C2H5OH. The responses of these hierarchical nanostructures to 10-100 ppm C2H5OH ranged from 15.7 to 177.7, which were 7-9 times higher than those of the agglomerated nanoparticles. 相似文献
115.
Syed M. Usman AliAuthor Vitae N.H. AlviAuthor VitaeZafar IbupotoAuthor Vitae Omer NurAuthor VitaeMagnus WillanderAuthor Vitae Bengt DanielssonAuthor Vitae 《Sensors and actuators. B, Chemical》2011,152(2):241-247
In this study, a potentiometric uric acid biosensor was fabricated by immobilization of uricase onto zinc oxide (ZnO) nanowires. Zinc oxide nanowires with 80-150 nm in diameter and 900 nm to 1.5 μm in lengths were grown on the surface of a gold coated flexible plastic substrate. Uricase was electrostatically immobilized on the surface of well aligned ZnO nanowires resulting in a sensitive, selective, stable and reproducible uric acid biosensor. The potentiometric response of the ZnO sensor vs Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (1-650 μM) suitable for human blood serum. By applying a Nafion® membrane on the sensor the linear range could be extended to 1-1000 μM at the expense of an increased response time from 6.25 s to less than 9 s. On the other hand the membrane increased the sensor durability considerably. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea. 相似文献
116.
Bai ShouliAuthor VitaeChen LiangyuanAuthor Vitae Hu JingweiAuthor VitaeLi DianqingAuthor Vitae Luo RuixianAuthor VitaeChung Chiun LiuAuthor Vitae 《Sensors and actuators. B, Chemical》2011,159(1):97-102
Quantum size ZnO crystals have been synthesized successfully by a room temperature sol-gel process. Oleic acid (OA) has been used as capping agent to control the particle size of ZnO. The crystal structure and size of the ZnO are characterized by the X-ray diffraction (XRD) and transmission electron microscope (TEM). The XRD results show the as-synthesized ZnO has hexagonal wurtzite structure and the average crystallite size is 5.7 nm which is little less than TEM result. It is testified by photoluminescence (PL) and Raman spectra that the quantum size ZnO keeps the crystal structure of the bulk ZnO and possesses more surface defects. The quantum size ZnO has the highest response of 280 to NO2 and the highest selectivity of 31 and 49 corresponding to CO and CH4 at operating temperature of 290 °C. The effect of calcination temperatures on sensing property and transient response of the ZnO sensor are also investigated. 相似文献
117.
Lexi Zhang Jianghong Zhao Haiqiang Lu Liming Gong Li Li Jianfeng Zheng Hui Li Zhenping ZhuAuthor vitae 《Sensors and actuators. B, Chemical》2011,160(1):364
Nanoparticle-assembled ZnO micro-octahedrons were synthesized by a facile homogeneous precipitation method. The ZnO micro-octahedrons are hexagonal wurtzite with high crystallinity. Abundant structure defects were confirmed on ZnO surface by photoluminescence. Gas sensors based on the ZnO micro-octahedrons exhibited high response, selectivity and stability to 1–1000 ppm formaldehyde at 400 °C. Especially, even 1 ppm formaldehyde could be detected with high response (S = 22.7). It is of interest to point out that formaldehyde could be easily distinguished from ethanol or acetaldehyde with a selectivity of about 3. The high formaldehyde response is mainly attributed to the synergistic effect of high contents of electron donor defects (Zni and VO) and highly active oxygen species (O2−) on the ZnO surface. 相似文献
118.
Mei ChenAuthor VitaeZhihua WangAuthor Vitae Dongmei HanAuthor VitaeFubo GuAuthor Vitae Guangsheng GuoAuthor Vitae 《Sensors and actuators. B, Chemical》2011,157(2):565-574
Hierarchical flower-like and 1D tube-like ZnO architectures were synthesized by a microemulsion-based solvothermal method. Technologies of XRD, SEM and TEM were used to characterize the morphological and structural properties of the products. The influence of the flower-like and tube-like morphologies on their NO2 sensing properties was investigated. The experimental results showed that high-sensitivity NO2 gas sensors were fabricated. The sensitivity of the tube-like ZnO gas sensor was much higher than that of the flower-like ZnO gas sensor and the tube-like ZnO gas sensor exhibited shorter response time. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique was employed to investigate the NO2 sensing mechanisms. Free nitrate ions, nitrate and nitrite were the main adsorbed species during the adsorption, and NO also existed in the initial period of surface reoxidation. Furthermore, N2O was formed via NO− and N2O2− stemmed from NO and increased upon rising temperature. Moreover, the PL spectra and the XPS spectra further proved that the intensity of donors (oxygen vacancy (VO) and zinc interstitial (Zni)) and surface oxygen species (O2− and O2) involved in the gas sensing mechanism leaded to the different sensitivities. 相似文献
119.
120.
Investigation on formaldehyde gas sensor with ZnO thick film prepared through microwave heating method 总被引:1,自引:0,他引:1
ZnO nanopowders were prepared through microwave heating method. ZnO thick film sensors were fabricated by using ZnO nanopowders as sensing materials. The phase composition and morphology of the material particles were characterized by means of X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The gas-sensing properties of the sensors based on ZnO nano-materials were investigated. It was found that the sensor based on ZnO nano-materials (low power, 10× 10 min) exhibited very high responses to benzene and toluene when operating at 440 and 370 °C, respectively; but the sensor based on ZnO (low power, 10× 10 min) showed very low responses to benzene and toluene when operating at 205–215 °C. The sensor based on ZnO (low power, 10× 10 min) showed high response and good selectivity to dilute formaldehyde when operating at 210 °C; especially, the response to 0.001 ppm HCHO attained 7.4 when operating at 210 °C. 相似文献