A review on the effect of metal doped ZnO nanostructures on ultraviolet photoconductive sensor performance (original) (raw)
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Highly Responsive UV Light Sensors Using Mg-Doped ZnO Nanoparticles
Journal of Sensors, 2016
Different concentrations of Mg-doped ZnO nanoparticles (NPs) were synthesized by coprecipitation technique at 60 ∘ C. XRD data are used to study phase purity and crystal structure in different doping concentrations. The results indicated that increasing the doping from 0∼7.5 wt.% caused a subsequent increase in FWHM in XRD and an associated systematic shift towards higher wavelength in the optical properties. Finally, the sensing of UV light is tested by observing the response of nanoparticles by exposing them to UV light and measuring the resistance in presence and absence of UV light.
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We report synthesis, electrical, optical, and UV sensing properties of morphology tuned one-dimensional ZnO nanostructures. Morphology tuning was achieved by varying the temperature using very simple vapor transport method. The structural, morphological, and compositional properties of the samples were investigated by powder X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, and energy dispersive analysis of X-rays spectroscopy. Photoluminescence and diffused reflectance spectroscopy were used to optically characterize films. The structural and morphological features revealed demonstrated that the synthesized nanostructures were high-density crystalline nanowires, nanorods, and nanobelts. Synthesized nanostructures were employed in UV sensing applications. The photosensors exhibit a current response range from 5 to 217 lA for UV light (365 nm) at room temperature. The sensor showed a relatively fast temporal response (0.25-35 s) and baseline recovery time (1-12 s) when irradiated with UV light. Response measurements showed that such a sensor is suitable for use as an optical switch. Recently, one-dimensional ZnO nanowires, nanobelts, and nanorods have shown potential as next-generation UV sensors as well as self-powered photodetectors [5, 15, 16]. UV sensors are highly desirable in many fields such as environmental studies, space communications, medical, and communication equipment [17, 18]. ZnO nanostructures are potential candidate for UV sensors due to their high surface to volume and ON/OFF current ratios [2], fast
Optical Materials, 2010
Aluminum (Al) doped zinc oxide (ZnO) thin films have been prepared on microscope glass substrate using sol-gel spin-coating method with different doping concentrations from 0 to 3 at.%. The thin films were characterized using X-ray diffractometer (XRD), UV-vis-NIR spectrophotometer, Current-Voltage (I-V) measurement system and photocurrent measurement system for applications in ultraviolet (UV) photoconductive sensor. From the XRD analysis, increasing of doping concentration affected structural properties of the thin film where c-axis orientation becomes weaker. UV-vis-NIR spectra reveals all films exhibit high transmission (>80%) in UV-NIR region. Improvement in electrical properties with dopant concentrations is observed as shown by I-V measurement results. 1 at.% Al doped ZnO thin film shows the highest photocurrent value after irradiated with UV lamp (365 nm).
Enhanced ultraviolet photo-response in Dy doped ZnO thin film
Journal of Applied Physics, 2018
In the present work, a Dy doped ZnO thin film deposited by the spin coating method has been studied for its potential application in a ZnO based UV detector. The investigations on the structural property and surface morphology of the thin film ensure that the prepared samples are crystalline and exhibit a hexagonal crystal structure of ZnO. A small change in crystallite size has been observed due to Dy doping in ZnO. AFM analysis ascertains the grain growth and smooth surface of the thin films. The Dy doped ZnO thin film exhibits a significant enhancement in UV region absorption as compared to the pure ZnO thin film, which suggests that Dy doped ZnO can be used as a UV detector. Under UV irradiation of wavelength 325 nm, the photocurrent value of Dy doped ZnO is 105.54 lA at 4.5 V, which is 31 times greater than that of the un-doped ZnO thin film (3.39 lA). The calculated value of responsivity is found to increase significantly due to the incorporation of Dy in the ZnO lattice. The observed higher value of photocurrent and responsivity could be attributed to the substitution of Dy in the ZnO lattice, which enhances the conductivity, electron mobility, and defects in ZnO and benefits the UV sensing property.
UV detectors based on nanocrystalline ZnO films
Technical Physics, 2008
Nanocrystalline films of zinc oxide deposited by rf magnetron sputtering are used as a working material of UV detectors. The photoelectric performance of UV detectors versus ZnO deposition conditions is studied. The influence of the surface topology of the UV detectors on their efficiency is examined with an atomic force microscope.
Applied Mechanics and Materials, 2015
Fabrication and performance of metal-semiconductor-metal (MSM)–type intrinsic zinc oxide-coated, aluminium-doped ZnO nanorod array-based ultraviolet photoconductive sensors were reported and discussed. The Al-doped ZnO nanorod arrays were prepared using sonicated sol-gel immersion method. The coating process of intrinsic ZnO onto Al-doped ZnO nanorod arrays was performed using radio-frequency (RF) magnetron sputtering at different deposition times varying from 0 to 10 min. We observed that responsivity of the sensors decreased with increasing intrinsic ZnO deposition time, decreasing from 4.81 A/W without coating to 1.37 A/W after 10 min of coating. Interestingly, the sensitivity of the sensors improved with intrinsic ZnO coating, having a maximum value of 19.0 after 1 min coating.
Japanese Journal of Applied Physics, 2012
Aluminium (Al)-doped zinc oxide (ZnO) nanorod arrays were prepared on a seed-layer-coated glass substrate by a sonicated sol-gel immersion method. We have shown, for the first time, that the thickness of the nanorod arrays can be increased incrementally without greatly affecting the diameter of the nanorods, by increasing the number of immersions. The field-emission scanning electron micrographs and thickness measurements revealed that the nanorods had diameters within the range from 40 to 150 nm and thicknesses from 629 to 834 nm with immersion times ranging from 1 to 5 h. The photoluminescence (PL) spectra revealed that the ZnO nanorod quality was enhanced with long immersion times as shown by an improvement in the ratio of the UV peak intensity to the visible emission peak intensity, or I UV =I vis. The thickness-dependent characteristic of Al-doped ZnO nanorod-array-based, UV photoconductive sensors was studied; minimising the thickness of the nanorod arrays was found to provide high responsivity and good performance. Our experiments showed that a decrease in the thickness of the nanorod arrays improved the responsivity and response time of the UV sensors, with a maximum responsivity of 2.13 A/W observed for a 629-nm-thick nanorod film.
Fabrication and characterization of ZnO film based UV photodetector
Journal of Materials Science: Materials in Electronics, 2008
ZnO films were deposited on Al 2 O 3 substrates by metalorganic chemical vapor deposition (MOCVD) at temperatures of 400, 450 and 500°C. The photoconductivity of the films has been analyzed for ultraviolet detector application. The changes in photoresponse and currentvoltage (I-V) are correlated with the deposition temperatures and microcrystalline structures. The study suggested that the photoresponse originating from bulk-and surfacerelated processes. For a film deposited at 400°C, a 1 ms fast rising time and a 5 ms fall time were observed. The photoresponsivity is *24 A/W with a 3 V bias.