scholarly journals Characterization of Ag/ZnO Nanorod Schottky Diode-Based Low-Voltage Ultraviolet Photodetector

NANO ◽  
2017 ◽  
Vol 12 (05) ◽  
pp. 1750063 ◽  
Author(s):  
Shaivalini Singh ◽  
S. Jit ◽  
Si-Hyun Park

Ultraviolet (UV) detection characteristics of Ag Schottky contacts with ZnO nanorods (ZnO-NRs) grown on Indium Tin Oxide (ITO)-coated glass substrates have been investigated. A low-temperature hydrothermal method was used for growing ZnO-NRs. Circular contacts of Ag were deposited above the ZnO-NRs/ITO samples using the shadow mask technique. The structural properties of the ZnO-NRs were characterized by using scanning electron microscopy (SEM), atomic force microscope (AFM) and X-ray diffraction (XRD). The results revealed a (0002) crystal orientation and a wurtzite hexagonal structure. The electrical characteristics of the Ag/ZnO-NR Schottky contacts were studied at forward applied bias over the range 0[Formula: see text]V to 1[Formula: see text]V, under dark and UV illumination. The dark and photocurrents were [Formula: see text][Formula: see text]A and [Formula: see text][Formula: see text]A, respectively, and the contrast ratio (ratio of photocurrent to dark current) was 1.67 at [Formula: see text]1.0[Formula: see text]V for these devices. The results show that these devices could be useful for cost-effective and low-voltage UV detection applications.

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Amrit Kaphle ◽  
Travis Reed ◽  
Allen Apblett ◽  
Parameswar Hari

Nanostructured ZnO thin films doped with cobalt from 5% to 20% were grown on glass substrates by a low-temperature chemical bath deposition (CBD) technique. We compared the doping efficiency of incorporating cobalt in ZnO nanostructured samples doped with cobalt via cobalt nitrate and cobalt chloride. The concentration of cobalt incorporated into the ZnO matrix was precisely determined using inductively coupled plasma mass spectroscopy (ICP-MS). Scanning electron microscopy (SEM) images showed that only at a 0.1 M ratio of the precursor solutions in CBD using cobalt nitrate as a dopant, the morphology of ZnO yielded hexagonally shaped nanorods. At a 1 M ratio of the precursor solutions, SEM images showed that the morphology of ZnO was nanoplatelets at all doping levels, irrespective of the doping method used. The synthesized nanostructures retained the wurtzite hexagonal structure only at 0.1 M precursor solution using cobalt nitrate doping, which was confirmed by X-ray diffraction (XRD) studies. In cobalt-doped samples using cobalt chloride as a dopant, XRD analysis confirmed the formation of a Simonkolleite structure. At 300°C, the Simonkolleite structure was converted to a wurtzite structure without changing the morphology. Electrical conductivity measurements at 300 K showed that ZnO nanorods doped with cobalt using cobalt nitrate yielded the lowest resistivity. The molarity of the precursor solution and dopant was found to have a substantial impact on the morphology and doping efficiency of the ZnO nanostructures.


2014 ◽  
Vol 974 ◽  
pp. 116-120
Author(s):  
Q.Z. Mehdi ◽  
Gurumurthy Hegde ◽  
Mohamad Ashry Bin Juusoh ◽  
Jinan B. Al-Dabbagh ◽  
Naser Mahmoud Ahmed

Indium tin oxide (ITO) thin films of 150 nm thickness were deposited on quartz glass substrates by RF sputtering technique, followed by thermal annealing treatment. In this technique, the samples have been annealed at different temperature, 300OC, 400OC, 500OC respectively in Argon gas flow. Structural and surface morphological properties were analyzed by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) after annealing. The XRD showed a polycrystalline structure of ITO film with maximum peak intensity at 2θ= 30.54, <222> orientation without any change in the cubic structure. Continuous and homogeneous films obtained by the AFM after annealing treatment. The visible spectrum from the spectrophotometer showed high transparency between 81% and 95% in the. Increasing the annealing temperature yields evenly distributed pyramidal peaks shaped particles with low roughness. Resistance of ITO thin film was significantly improved from 8.75 kΩ to 1.96 kΩ after 10 minute from 300OC to 500OC annealing temperatures respectively under Argon gas flow. ITO films physical properties would be well improved by this method which is highly suitable for cost effective photonic devices.


Author(s):  
Ashish Kumar ◽  
Arathy Varghese ◽  
Vijay Janyani

AbstractThis work presents the performance evaluation of Graphene/ZnO Schottky junctions grown on flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates. The fabricated structures include chemical vapour deposition grown graphene layer on ITO-coated PET substrates. Polymethyl methacrylate assisted transfer method has been employed for the successful transfer of graphene from Cu substrate to PET. The smaller D-band intensity (1350 cm−1) compared to G-band (1580 cm−1) indicates good quality of carbon lattice with less number of defects. High-quality ZnO has been deposited through RF sputtering. The deposited ZnO with grain size 50–95 nm exhibited dislocation densities of 1.31270 × 10–3 nm−2 and compressive nature with negative strain of − 1.43156 GPa. Further, the electrical and optical characterization of the devices has been done through device I–V characterization and UV detection analysis. The UV detection capability of the device has been carried out with the aid of a UV-lamp of 365 nm wavelength. The fabricated graphene/ZnO photodetector showed good response to UV illumination. The device performance analysis has been done through a comparison of the device responsivity and detectivity with the existing detectors. The detectivity and responsivity of the fabricated detectors were 7.106 × 109 mHz1/2 W−1 and 0.49 A W−1, respectively.


2021 ◽  
Vol 2070 (1) ◽  
pp. 012039
Author(s):  
Ankit Rai Dogra ◽  
Vandna Sharma ◽  
Partha Khanra ◽  
Pankaj Kumar

Abstract Recently, various techniques such as self-assembly, chemical vapour deposition and capillary method etc. are used for nanoparticles (NPs) deposition on the conductive substrates for the vertical alignment (VA) of liquid crystals (LCs). The initial VA of LCs in display devices have the potential impact on industry and various electro-optic devices applications. In the present work, vertical orientation of LCs was controlled on silica (SiO2) nanoparticles (NPs) layer deposited on indium tin oxide (ITO) glass substrates using spin coating method. The VA LC cell was also prepared for conventional polyimide coated ITO glass substrates. The morphological images showed the initial darker textures under crossed polarizers and conoscopic image with dark cross confirmed the VA of LC on SiO2 NPs coated substrates analogous to the conventional VA LC cell. Further, electro-optic results revealed the reduction in applied voltage and better contrast ratio for SiO2 NPs coated VA LC cell compared with polyimide coated VA LC cell.


Author(s):  
T. Joseph Sahaya Anand ◽  
Rajes K. M. Rajan ◽  
Md Radzai Said ◽  
Lau Kok Tee

Thin films of nickel chalcogenide, NiX2 (X= Te, Se) have been electrosynthesized on indium-tin-oxide (ITO) coated glass substrates. The films were characterized for their structural, morphological and compositional characteristics. Consisting of transition metals and chalcogenides (S, Se and Te), they show promising solar absorbent properties such as semiconducting band gap, well adhesion to substrate and good conversion with better cost-effective. Cyclic voltammetry experiments have been done prior to electrodeposition in order to get the electrodeposition potential range where the observable reduction range is between -0.9-(-1.1) V. Their optical and semiconducting parameters were also analysed in order to determine the suitability of the thin films for photoelectrochemical (PEC) / solar cell applications. Structural analysis via X-ray diffraction (XRD) analysis reveals that the films are polycrystalline in nature. Scanning electron microscope (SEM) studies reveals that the films were adherent to the substrate with uniform and pin-hole free. Compositional analysis via energy dispersive X-ray (EDX) technique confirms the presence of Ni, Te, and Se elements in the films. The optical studies show that the films are of direct bandgap. Results on the semiconductor parameters analysis of the films showed that the nature of the Mott-Schottky plots indicates that the films obtained are of p-type material.


2008 ◽  
Vol 54 ◽  
pp. 305-310 ◽  
Author(s):  
Parameswar Hari ◽  
Daryl Spencer

ZnO nanorods grown by chemical bath methods are of great interest in photovoltaic and electronic device applications because they offer low cost, low temperature deposition techniques compared to conventional molecular beam vapor deposition and sputtering methods. Our previous studies of ZnO nanorods grown by chemical bath technique on indium tin oxide (ITO) coated glass substrates at 90 C for 8-10 hours resulted in uniform growth of hexagonally shaped closed nanorod structures. We used scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques to map changes in surface morphology of nanorods grown on various substrates. Morphology of ZnO nanorods at temperatures 80C, 90C, 95C and 100C for 9 hours of hydrothermal growth also resulted in hexagonal shaped nanorods of various sizes and surface roughness. In addition, we studied the changes in surface morphology of ZnO nanorods on indium tin oxide coated glass, aluminum coated glass, and conducting tin oxide glass substrate. In this paper, we present quantitative data on changes in cluster size and shape of nanorods as the growth substrate and deposition temperature are varied. We will also discuss conductivity changes of ZnO nanorods deposited on various substrates.


2009 ◽  
Vol 1 (2) ◽  
pp. 18-20
Author(s):  
Dahyunir Dahlan

Copper oxide particles were electrodeposited onto indium tin oxide (ITO) coated glass substrates. Electrodeposition was carried out in the electrolyte containing cupric sulphate, boric acid and glucopone. Both continuous and pulse currents methods were used in the process with platinum electrode, saturated calomel electrode (SCE) and ITO electrode as the counter, reference and working electrode respectively. The deposited particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that, using continuous current deposition, the deposited particles were mixture of Cu2O and CuO particles. By adding glucopone in the electrolyte, particles with spherical shapes were produced. Electrodeposition by using pulse current, uniform cubical shaped Cu2O particles were produced


Author(s):  
Minakshi Chaudhary ◽  
Yogesh Hase ◽  
Ashwini Punde ◽  
Pratibha Shinde ◽  
Ashish Waghmare ◽  
...  

: Thin films of PbS were prepared onto glass substrates by using a simple and cost effective CBD method. Influence of deposition time on structural, morphology and optical properties have been investigated systematically. The XRD analysis revealed that PbS films are polycrystalline with preferred orientation in (200) direction. Enhancement in crystallinity and PbS crystallite size has been observed with increase in deposition time. Formation of single phase PbS thin films has been further confirmed by Raman spectroscopy. The surface morphology analysis revealed the formation of prismatic and pebble-like PbS particles and with increase in deposition time these PbS particles are separated from each other without secondary growth. The data obtained from the EDX spectra shows the formation of high-quality but slightly sulfur rich PbS thin films over the entire range of deposition time studied. All films show increase in absorption with increase in deposition time and a strong absorption in the visible and sub-band gap regime of NIR range of the spectrum with red shift in band edge. The optical band gap shows decreasing trend, as deposition time increases but it is higher than the band gap of bulk PbS.


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