On the UV-light-induced Desorption/Adsorption Mechanism of Atmospheric Species in Solution-processed Zinc Oxide Thin Films

MRS Advances ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 111-117
Author(s):  
José Bruno Cantuária ◽  
Giovani Gozzi ◽  
Lucas Fugikawa Santos
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Uv Light ◽  
Atmospheric Oxygen ◽  
Low Cost ◽  
Environmental Parameters ◽  
Zno Films ◽  
Desorption Rate ◽  
Transparent Semiconductor

AbstractZinc oxide (ZnO) is a n-type transparent semiconductor which can be processed by low cost techniques (such as spray-pyrolysis and spin-coating) and can be applied as the active layer of thin-films transistors (TFTs). The electrical properties of ZnO films are strongly affected when the device is exposed to room conditions and/or UV-light, suggesting possible applications as UV or/and gas sensors. Atmospheric oxygen molecules adsorbed on ZnO surface act as charge traps, decreasing the material conductivity. The incidence of UV-light causes an increase of the material conductivity due to the photogeneration of electron-hole pairs via direct band-to-band transitions (classic photoconductivity process) and due to the desorption of oxygen molecules, which presents a relatively slower response and is a less understood mechanism. In the current paper, we study the influence of environmental parameters, such as temperature, humidity and UV-light intensity, on the electrical properties of spin-coated ZnO thin films to understand the role of the desorption mechanism on the photoconductivity process. The analysis of the device current vs. time curves shows the existence of two light-induced desorption mechanisms: i) one which increases the electrical conductivity of the ZnO film (desorption-like process) and ii) a second one which decreases the conductivity (adsorption-like process). A Plackett-Burman design of experiment (DOE) was used to study the influence of characterization factors like UV intensity, temperature and humidity on electrical parameters obtained from the experimental curves. We observed that the desorption-like process is a first order mechanism, exhibiting desorption rate proportional to n(t), where n(t) represents the adsorbate concentration as a function of the time, whereas the adsorption-like mechanism exhibits a desorption rate proportional to the forth power of n(t).

Studies of MZS and MZOS Structures with Zinc Oxide Deposited by Conventional Rf Diode and Magnetron Sputtering Techniques

1986 ◽  
Vol 77 ◽  
Author(s):  
S. N. Venkatesh ◽  
E. S. Ramakrishnan ◽  
K. C. Jungling ◽  
S. B. Krupanidhi
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Magnetron Sputtering ◽  
Comparative Evaluation ◽  
Growth Process ◽  
Zno Films ◽  
Electrical Characteristics ◽  
Ceramic Target ◽  
Sputter Deposited

ABSTRACTHighly crystalline and c-axis oriented zinc oxide thin films were sputter deposited from a ceramic target using rf diode and magnetron sputtering techniques. A comparative evaluation of structure and electrical characteristics of ZnO films in the MZS and MZOS configurations is presented and the results are discussed. The physical and electrical properties were significantly influenced by highly energetic particles originating from the presence of oxygen neutrals in the plasma during the growth process and the behavior differed between the diode and magnetron sputtering processes.

Fabrication and Characterization of ZnO Thin Films by Sol-Gel Spin Coating Method for pH Measurement

2015 ◽  
Vol 1109 ◽  
pp. 99-103 ◽  
Author(s):  
K.L. Foo ◽  
U. Hashim ◽  
Chun Hong Voon ◽  
M. Kashif
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Low Cost ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Zno Films ◽  
Zno Thin Film ◽  
Coating Method ◽  
Transparent Semiconductor

Transparent semiconductor ZnO thin films deposited on interdigitated electrode (IDE) substrate substrates were obtained by low-cost sol-gel method. The coated ZnO films were annealed in furnace at 500°C for 2 hours. The influence of surface morphologies, crystallization and optical properties was investigated. The structural properties of the annealed ZnO thin films were examined with FESEM and AFM. XRD result shows that all polycrystalline ZnO thin film after annealing have the orientation along the (002) plane. Both FESEM and XRD results revealed that ZnO thin films were composed of hexagonal ZnO crystals in nanoscale dimensions. Moreover, UV-Vis was employed to study the optical properties of the ZnO films. Besides that, the deposited ZnO thin film will further use for pH by I-V curve tracer.

Optical and electrical properties of p-type zinc oxide thin films synthesized by ion beam assisted deposition

2005 ◽  
Vol 492 (1-2) ◽  
pp. 203-206 ◽  
Author(s):  
Zhi Yan ◽  
Zhi Tang Song ◽  
Wei Li Liu ◽  
Qing Wan ◽  
Fu Min Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Ion Beam ◽  
Optical And Electrical Properties ◽  
Oxide Thin Films ◽  
Ion Beam Assisted Deposition ◽  
P Type

Sol-gel-derived gallium nitride thin films for ultraviolet photodetection

2019 ◽  
Vol 36 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Chee Yong Fong ◽  
Sha Shiong Ng ◽  
NurFahana Mohd Amin ◽  
Fong Kwong Yam ◽  
Zainuriah Hassan
Keyword(s):  
Thin Films ◽  
Dark Current ◽  
Uv Light ◽  
Low Cost ◽  
Sol Gel ◽  
Contrast Ratio ◽  
Uv Photodetector ◽  
Content Type ◽  
Barrier Heights ◽  
Coating Method

Purpose This study aims to explore the applicability of the sol-gel-derived GaN thin films for UV photodetection. Design/methodology/approach GaN-based ultraviolet (UV) photodetector with Pt Schottky contacts was fabricated and its applicability was investigated. The current-voltage (I-V) characteristics of the GaN-based UV photodetector under the dark current and photocurrent were measured. Findings The ideality factors of GaN-based UV photodetector under dark current and photocurrent were 6.93 and 5.62, respectively. While the Schottky barrier heights (SBH) for GaN-based UV photodetector under dark current and photocurrent were 0.35 eV and 0.34 eV, respectively. The contrast ratio and responsivity of this UV photodetector measured at 5 V were found to be 1.36 and 1.68 μA/W, respectively. The photoresponse as a function of time was measured by switching the UV light on and off continuously at different forward biases of 1, 3 and 6 V. The results showed that the fabricated UV photodetector has reasonable stability and repeatability. Originality/value This work demonstrated that GaN-based UV photodetector can be fabricated by using the GaN thin film grown by low-cost and simple sol-gel spin coating method.

Zinc Oxide Thin Films Grown on Nanostructured Al Thin Layer/Glass Substrate by RF Magnetron Sputtering

2011 ◽  
Vol 239-242 ◽  
pp. 777-780
Author(s):  
Ting Zhi Liu ◽  
Shu Wang Duo ◽  
C Y Hu ◽  
C B Li
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Thin Layer ◽  
Glass Substrate ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
Zno Film ◽  
Substrate Roughness ◽  
Axis Orientation

ZnO films were deposited on nanostructured Al (n-Al) /glass substrate by RF magnetron sputtering. The results shows that the relation (I (002) /I (100) ≈ I annealed (002)/I annealed (100) ≈1.1) shows the rough n-Al surface is suitable for the growth of a-axis orientation. Meanwhile, the influences of substrate roughness, crystallinity and (101) plane of ZnO film deposited on n-Al layer have been discussed. XPS implies more oxygen atoms are bound to Aluminum atoms, which result in the increase of high metallic Zn in the film.

Stability Studies on Optical and Structure Properties of Zinc Oxide Thin Films Exposed to Different Environment

2013 ◽  
Vol 667 ◽  
pp. 549-552
Author(s):  
A.S.M. Rodzi ◽  
Mohamad Hafiz Mamat ◽  
M.N. Berhan ◽  
Mohamad Rusop Mahmood
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Zinc Oxide ◽  
Absorption Coefficient ◽  
Near Infrared ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Zno Films ◽  
Zno Thin Film ◽  
Oxide Thin Films

The properties of zinc oxide thin films were prepared by sol-gel spin-coating method have been presented. This study based on optical and electrical properties of ZnO thin film. The effects of annealing temperatures that exposed with two environments properties have been investigated. Environments exposed in room (27°C) and hot (80°C) temperatures which are stored by various days. Solution preparation, thin film deposition and characterization process were involved in this project. The ZnO films were characterized using UV-Vis-NIR spectrophotometer for optical properties. From that equipment, the percentage of transmittance (%) and absorption coefficient spectra were obtained. With two environments showed have different absorption coefficient are reveal and all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties. From SEM investigations the surface morphology of ZnO thin film shows the particles size become smaller and denser in hot temperatures while in room temperatures have porosity between particles.

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