hussein abdullah hameed alshamarti

Abstract In this work, ZnO nanorods (NRs) were doped with (0, 3, and 6)% Mn and grown on the glass slide by the Microwave-Assisted Chemical Bath Deposition (MACBD) method, at 80 °C. Al contacts were evaporated on the prepared thin film by thermal evaporation technique to produce metal-semiconductor-metal detector (MSM). The novelty of this work is to obtain a UV detector device that works at room temperature using a simple method and low synthesis temperature. The structural properties and the surface morphology of the prepared samples were investigated. The XRD results of un-doped and Mn-doped Zinc Oxide (MZO) NRs reveals sharp and strong peaks, confirming high crystallinity structure. The FE-SEM images showed that the Zinc Oxide NRs were good-aligned and well distributed throughout the glass substrate. At a room temperature, the fabricated detectors were showed an important difference among the current density of the UV wavelengths 365 nm, 385 nm and dark current density. Under 5 V of the applied source voltage, the responsivity of MSM photodetectors based on MZO (0, 3, and 6)% were (0.0361, 0.044 and 0.0765) A/W at a wavelength 365 nm, (0.0232 and 0.0324 and 0.0391) at UV wavelength of 385 nm, at power density of 40 μW/cm2, respectively. All devices in this work demonstrated high response to the UV radiation and showed almost no response to the visible spectrum.

Abstract In this work, un-doped and Manganese doped Zinc Oxide Nanorods (NRs) thin films were grown on the glass substrates using chemical bath deposition method (CBD) at 80 °C temperature. The effect of Mn content (0, 2 and 4%) on the structural, morphology, optical and photoluminescence characteristics of ZnO NRs films was investigated. The XRD patterns of un-doped and Mn-doped ZnO NRs demonstrate sharp and strong peaks together with high crystalline structure. The FESEM images showed that the nanorods of ZnO and Mn:ZnO were well-aligned and distributed throughout the films. The absorption edge was observed to be blue-shifted and the optical energy gap was found to be widening from (3.21, to 3.31) eV with increased Mn content. The photoluminescence spectrum (PL) of Mn-doped samples was examined, at room temperature, and revealed of highly UV emission, whereas the green-yellow wavelengths emissions were enhanced with increased Mn content. Current-voltage (I-V) characteristics showed that the photocurrents of all prepared samples are enhanced and the Mn doped samples showed a good response, under UV light.

Scanning electron microscopy (SEM) images is a special and important type of images that need special enhancement to get more information for the nanoscale phenomenon. Many studies have been introduced in this purpose with the traditional enhancement and suggested methods but here in this study a new method represented in a hybrid filter formed by mean and Sobel that are common filters in enhancement and edge detection respectively. The results are evidence for the success of the new filter using a stander image with many noise levels before applying it on the SEM image. The new filter gave better results comparing with the mean filter as a traditional enhancement filter. The new filter is added as new technique filter for Nano scale images.

ZnO and Al-doped ZnO nanorods (NRs) were synthesis to fabricated UV detector devices deposited on N-type Si, Two methods used to synthesis sol-gel and Chemical bath deposition (CBD). The crystalline properties indicated shifting in the peaks of XRD patterns of Al-doped ZnO relative to ZnO patterns. The detection of UV radiation was apparent through the results of the UV detector parameters. The doping process by Al improved the characterization of photo-detector devices where the external quantum efficiency (EQE) of enhancement from 67.94% to 135.89% at wavelength 365nm and reached to 901.8% at wavelength 385 nm.

Abstract Magnesium-doped Zinc oxide (ZnO: Mg) nanorods (NRs) films and pure Zinc oxide deposited on the p-silicon substrates were prepared by hydrothermal method. The doping level of the Mg concentration (atoms ratio of Mg to Zn was chosen to be 0.75% and 1.5%. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) were performed to characterize the prepared films. X-ray diffraction analysis showed a decrease in the lattice parameters of the Mg-doped ZnO NRs. Under 10V applied bias voltage, the responsivity of p-n junction UV photodiode based on pure ZnO and Mg: ZnO with doping ratio (0.75% and 1.5%) was 0.06 A/W and (0.15A/W and 0.27A/W) at UV illumination of wavelength 365 nm respectively, 0.071 A/W and (0.084A/W and 0.11A/W) for UV wavelength of 385 nm with power density 40μW/cm2, respectively. The Mg-doped ZnO NRs photodiode exhibited high photosensitivity, fast response and fall times, and good orientation properties.

In this work, the pure Zinc oxide (ZnO) nanorods and ZnO doped by Copper, Indium and Magnesium nanorods/nanotubes were prepared by hydrothermal method. The MSM UV photodetectors and photodiodes applications were deposition based on the glass and p-type Silicon (1 0 0) substrates respectively. The Cu doping ratio was 2.5 % and 5 % of Zn ratio that prepared on glass substrates while it was 1.5 % and 3 % for samples which prepared onto Si substrates. Indium doping ratio was 2 % and 4 % of Zn ratio that prepared on glass substrates while it was 1% and 2% for samples which prepared onto the Si substrates. Finally, the Mg doping ratio was 2% and 6% of Zn atoms that prepared on glass substrates, while it was 0.75 % and 1.5 % for samples which prepared onto the Si substrates. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL), and UV- Vis were performed to characterize the prepared films. The intensity of XRD peaks of pure ZnO nanorods and ZnO doped demonstrates a poly crystalline and hexagonal wurtzite structure. The FESEM images show that the average diameters of ZnO NRs, Cu (5%) NRs, In (4%) NRs and Mg (6%) nanotubes were 40 to 80 nm, 30 to 60 nm, 50 to 90 nm and 60 to 80 nm, respectively. The band gap of undoped ZnO nanorods /glass was found to be 3.12eV, while the energy gap of Cu-doped ZnO nanorods/ glass and In-doped ZnO nanorods/glass were shifted towards the lower energy gap. By contrast, the Mg-doped ZnO nanotubes/glass was shifted towards the higher energy gap as Mg concentration was increased. All of these samples were successfully examined for metal-semiconductor- metal (MSM) UV photodetectors and photodiodes applications using aluminum 7 (Al) electrodes. The maximum quantum efficiency and responsivity for all the detectors which based on pure and ZnO doped were around the wavelength of 390 nm ± 5 nm. Certain properties of all detectors were measured under variable voltage bias and wavelengths. Furthermore, the characteristics of the diodes in dark and under the light were calculated for pure and doped ZnO at room temperature.