Search query: vanadium doped zinc oxide thin films

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abstract: We demonstrate the electro thermal control of aluminum doped zinc oxide (Al:ZnO) /vanadium dioxide (VO2) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO2 thin film to induce its semiconductor metal transition (SMT) The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO2 thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO2 thin film, which inhibits oxidation to a more energetically favorable and stable V2O5 phase. It also decreases the SMT of the VO2 thin film by approximately 5 10 degC because of an additional stress induced on the VO2 thin film and/or an alteration of the oxygen vacancy concentration in the VO2 thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near room temperature SMT.
author_names: Jonathan Skuza

D W Scott

Rajeh Mundle

Asima Pradhan
title: Electro thermal control of aluminum doped zinc oxide/vanadium dioxide multilayered thin films for smart device applications
venue: Scientific reports
year: 2016

abstract: The transparent conducting properties of vanadium doped indium zinc oxide (VIZO) have been investigated as a function of V doping concentration. The VIZO film demonstrated an average transmittance of above 86% in the visible range, and the sheet resistance showed 10.81 O/square with a V doping concentration of 0.18% In order to verify the applicability as a transparent conductor, the figure of merit was obtained to be 2.07 x 10 2 O 1. The changes of electrical characteristics could be correlated with the changes of the electronic structure, such as the oxidation state and the band edge defect states below the conduction band. By applying the optimal condition, the VIZO film achieved a high workfunction of 5.16 eV.The transparent conducting properties of vanadium doped indium zinc oxide (VIZO) have been investigated as a function of V doping concentration. The VIZO film demonstrated an average transmittance of above 86% in the visible range, and the sheet resistance showed 10.81 O/square with a V doping concentration of 0.18% In order to verify the applicability as a transparent conductor, the figure of merit was obtained to be 2.07 x 10 2 O 1. The changes of electrical characteristics could be correlated with the changes of the electronic structure, such as the oxidation state and the band edge defect states below the conduction band. By applying the optimal condition, the VIZO film achieved a high workfunction of 5.16 eV.
author_names: Sera Kwon

Deuk Young Kim

Byung Hyuk Jun

Kwun-Bum Chung
title: Optimization of the electrical and optical properties of vanadium doped InZnO thin films
year: 2018

author_names: Marco Galvez-Saldana

Gina Montes-Albino

O Perales-Perez
title: Ferromagnetism in Nanocrystalline Powders and Thin Films of Cobalt Vanadium co doped Zinc Oxide
year: 2012

abstract: Abstract Transparent conducting oxide thin films are used as front contact material for dye sensitized solar cells. This study investigated the effects of chromium (Cr) and vanadium (V) contents on the chemical and heat stability properties of aluminum doped zinc oxide (AZO) thin films using pulsed direct current magnetic sputtering on Corning 1737F glass substrates. The experimental results show that Cr and V doping is useful for improving the chemical and thermal stability of AZO films. The energy gap for AZO thin films is between 3.65 and 3.69 eV. The resistivity of the AZO:Cr:V thin film was 4.23 x 10 4 O cm at a Cr/V ratio of 0.30/0.23 wt. deposition power of 150 W, working distance of 5.5 cm, substrate temperature of 473 K, working pressure of 0.4 Pa, and frequency of 10 kHz. This value is lesser than (and therefore superior to) the resistivity of SnO 2 :F (FTO) films (6.5 x 10 4 O cm) but greater than that of SnO 2 :In (ITO) thin films (1.2 x 10 4 O cm) The resistivity increased by about 0.27% after electrolyte etching, which is similar to the 0.16% increase observed for the ITO thin film. After a thermal cycle test at 673 K, the resistivity of the AZO:Cr:V film increased to 5.42 x 10 4 O cm, which is better than the resistivity of the ITO and FTO films after the same thermal cycle.
author_names: Yi-Cheng Lin

C H Chang

C H Shen

P Wang

Y C Lee
title: The characteristics of chemical and heat stability properties of chromium vanadium aluminum co doped zinc oxide films for dye sensitized solar cells
year: 2010

abstract: Vanadium doped ZnO (VZO) thin films were grown by RF magnetron sputtering, starting from a ZnO:V ceramic target. The crystal structure, chemical composition, electric and piezoelectric properties of the films were investigated either on the as grown thin films or after a post deposition rapid thermal annealing (RTA) treatment performed at 600 degC for different lengths of time (1 and 5 min) in an oxygen atmosphere. Substitutional doping of Zn2+ with V3+ and V5+ ions strongly deteriorated the hexagonal wurtzite ZnO structure of the as grown thin films due to lattice distortion. The resulting slight amorphization led to a poor piezoelectric response and higher resistivity. After the RTA treatment, strong c axis oriented VZO thin films were obtained, together with a partial conversion of the starting V3+ ions into V5+ The improvement of the crystal structure and the stronger polarity of both V3+ O and V5+ O chemical bonds, together with the corresponding easier rotation under the application of an external electric field, positively affected the piezoelectric response and increased conductivity. This was confirmed by closed loop butterfly piezoelectric curves, by a maximum d33 piezoelectric coefficient of 85 pm*V 1, and also by ferroelectric switching domains with a well defined polarization hysteresis curve, featuring a residual polarization of 12.5 mCcm 2.
author_names: Marco Laurenti

Micaela Castellino

Denis Perrone

Abil Sh Asvarov

Giancarlo Canavese

Alessandro Chiolerio
title: Lead free piezoelectrics: V3+ to V5+ ion conversion promoting the performances of V doped Zinc Oxide
venue: Scientific reports
year: 2017

abstract: In this paper, transparent conducting thin films based on both undoped and vanadium (V) doped zinc oxide Zn1 xVx O (x 3, 5, 7 at. were studied. The thin films were prepared using a simple low cost deposition technique called spray pyrolysis (SP) The layers were deposited onto preheated glass substrates at 450 degC. The effect of vanadium on the microstructural, the morphological and the optical properties of ZnO material was carried out using X ray diffractometer (XRD) micro Raman spectroscope, scanning electron microscope (SEM) energy dispersive analysis by X ray (EDX) and UV Vis NIR spectrophotometer. We have demonstrated that doping with 3 at. of V enhances the crystallinity of the films by estimating the grain size value, the dislocation density and the residual stress. Also, the SEM images have demonstrated that the vanadium concentrations do effect in the thin films morphology, from hexagonal shaped grains to rounded crystals for higher doping concentrations. The optical analysis revealed that doping with 3 at. of vanadium shows a remarkable enhancement in the average transmittance in the visible range 89% and in the band gap energy (3.3 eV) Moreover, the disorder inside the samples was estimated using Urbach equation. Therefore, the microstructural, the morphological and the optical results approve that doping with 3 at. of V in ZnO lattices gives interesting results for the optical window material for solar cells application.
author_names: Hajar Ftouhi

Zouhair El Jouad

Mohammed Jbilou

M Diani

Mohammed Addou
title: Study of microstructural, morphological and optical properties of sprayed vanadium doped ZnO nanoparticles
venue: The European Physical Journal Applied Physics
year: 2019

abstract: Three types of ZnO based thin films were deposited under different deposition parameters using DC magnetron reactive sputtering technique over glass and n type (100) highly oriented silicon substrates: un doped ZnO films, Vanadium doped Zinc Oxide films and Aluminium doped Zinc Oxide films. ZnO:V films were co sputtered using two different magnetrons with Zinc (99,99% and Vanadium (99,99% targets, while pure ZnO and ZnO:Al films were sputtered using a single magnetron, placing an aluminium thin plate over the Zinc target in the case of ZnO:Al films. In all cases oxygen was used as the reactive gas and argon as the inert gas for creating the plasma. Previous to the deposition of the doped films, pure Zinc Oxide and pure Vanadium Oxide films were deposited separately to optimise some of their individual sputtering parameters and for following comparison. After characterization of all the films and result analysis, the most suitable and adjusted sputtering parameters were chosen to fabricate a piezoelectric thin film vibration energy harvesting device. Three different types of films were used for the device fabrication and testing, one un doped ZnO and two Vanadium doped ZnO films, in order to compare their vibration response and energy harvesting capabilities. For device testing different experiments were carried on including: Ultrasonic vibrations, mobile phone vibrations, cantilever vibrations and knocking induced vibrations. The films showed good piezoelectric activity, generating voltages in the order of tens to hundreds of mV under the different vibration conditions.
author_names: Albert Serra Torrent
title: Studies on zinc oxide based thin films for energy harvesting applications
year: 2013

abstract: The vanadium oxide thin films are prepared on zinc selenide by DC magnet sputtering method. The components are gotten using The X ray photoelectron spectroscopy (XPS) It's phase transition temperature can be changed by doping. Utilizing the Castep program package of the Material Studio simulation tool, based on local density function approximation and pseudopotential method, optimization for the geometric structure of vanadium dioxides is accomplished with the BFGS calculate way. The phase transition temperature of the vanadium oxide thin films doped with Cr and Al is higher; and doped with W and F is lower.
author_names: Xue-song Tian

Qi Wang

Jian-feng Sun

Z Fan
title: The calculation of doped vanadium dioxide thin films
venue: 2013 International Conference on Optoelectronics and Microelectronics (ICOM)
year: 2013

abstract: Abstract The effect of vanadium (V) doping on amorphization of zinc oxide (ZnO) thin films deposited on c plane sapphire substrate at room temperature by RF magnetron sputtering was investigated. From the in plane X ray diffraction measurements, the diffraction intensity from 30deg rotated domains observed in the ZnO film weakened with increasing V concentration. Faint diffractions from both the 30deg rotated and normal domains were seen in the V doped ZnO (VZO) film of 1.7 at. V, and relatively strong diffractions only from the normal domain were observed at 2.1 at. V while the 30deg rotated domains diminished. There were only weak normal domains for VZO over 2.4 at. V. Concerning the c axis orientation, the broad (0002) diffraction peaks were observed in all VZO films, and the peak was the widest for the 3.8 at. VZO film. From the dependence of crystallinity on thickness for the highly doped VZO (V: 3.8 at. films, the c axis orientation deteriorated with increasing film thickness and no diffraction signal was seen for the VZO films over 35 nm thick. This means that the VZO film aligned by the c plane sapphire grew only at the initial stage, but an accumulation of disordered layers worsened the crystallinity with thickening the film. From the above mentioned results, even in the ZnO film in which the grains tend to align to the c axis orientation preferentially, the doping of transition metals, like V in this study, plays an effective reaction to form the pseudo amorphous thin film. It is considered that this phenomenon is attributed to the feature of transition metal in which the transition metal atoms can take a state of various valence or coordination numbers.
author_names: Akihiro Watanabe

Hiroshi Chiba

Tomoyuki Kawashima

Katsuyoshi Washio
title: Effect of vanadium doping on amorphization of ZnO thin films on c plane sapphire substrate
year: 2016

abstract: Abstract Thin films of vanadium doped zinc oxide with different vanadium doping levels (0, 1, 2 and 3 at% were deposited on glass substrates by employing an inexpensive, simplified spray technique using at relatively low substrate temperature (460 degC) The effect of V doping on the structural, morphological and optical properties of the films was investigated by Mhamdi et al. (2013) The X ray diffraction analysis shows that the films were well crystallized in wurtzite phase with the crystallites preferentially oriented toward (0 0 2) direction parallel c axis. As also that the average particle size along the surface of the films decreases with increasing of concentration of vanadium. In this work we study the AC and DC conductivity and gas sensor application on ZnO:V thin films. The dielectric properties of ZnO:V thin films were studied by means of complex impedance spectroscopy and frequency dependence of conductivity measured from the impedance data at a range of frequency intervals between 10 Hz and 13 MHz with a temperature between 355 and 445 degC. The frequency dependence of the dielectric constant e' dielectric loss e' loss tangent (tan d) and AC electrical conductivity (sAC) of the layers was subsequently investigated. In literature, we have shown in previous papers that structural and surface morphology of ZnO thin films, prepared by spray, plays an important role in the gas detection mechanism. In this article, we have studied the response evolution of ZnO:V sensors ethanol versus time and working temperature, relative doping and the concentration of the ethanol vapor.
author_names: Ammar Mhamdi

Ahmed Labidi

Ben Souissi

Massoud Kahlaoui

Ayse Yumak

Karem Boubaker

A Amlouk

Mosbah Amlouk
title: Impedance spectroscopy and sensors under ethanol vapors application of sprayed vanadium doped ZnO compounds
year: 2015