Near surface characteristics of highly sensitive metal oxide thin films

MRS Proceedings ◽

10.1557/proc-828-a1.5 ◽

2004 ◽

Vol 828 ◽

Author(s):

G. Kiriakidis

Keyword(s):

Thin Films ◽

Secondary Ion Mass Spectrometry ◽

Gas Sensing ◽

High Sensitivity ◽

Surface Characteristics ◽

Metal Oxide Thin Films ◽

Near Surface ◽

Dc Sputtering ◽

Deposition Parameters ◽

Temperature And Growth

ABSTRACTWe present the gas sensing properties of InOx thin films deposited by dc sputtering and ZnOx thin films deposited both by dc sputtering and PLD. The sensitivity of the films towards ozone is correlated with the deposition parameters like film thickness, substrate deposition temperature and growth rate. Secondary Ion Mass Spectrometry (SIMS) analysis showed a noticeable deficit in oxygen in the top 5 nm for films in the “conducting” state, i.e., after UV exposure. Analysis of the sensing response for alumina-based transducers of InOx thin films revealed high sensitivity (less than 25 ppb) with fast and stable response towards ozone while ultimate sensitivity levels down to 10 ppb for ozone and 50 ppb for NO2 were achieved. Surface topography study of ZnOx films utilizing optical, AFM and SEM analyses has shown a distinct surface morphology variation correlated to the growth technique It is demonstrated that PLD leads to very rough surfaces with characteristic non-coordinated columnar features in contrast with the rather smooth surfaces obtained by sputtering.

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Developing GLAD Parameters to Control the Deposition of Nanostructured Thin Film

Sensors ◽

10.3390/s22020651 ◽

2022 ◽

Vol 22 (2) ◽

pp. 651

Author(s):

Jakub Bronicki ◽

Dominik Grochala ◽

Artur Rydosz

Keyword(s):

Thin Films ◽

Gas Sensing ◽

Glancing Angle Deposition ◽

Metal Oxide Thin Films ◽

Nanostructured Thin Film ◽

Sensing Applications ◽

Deposition Parameters ◽

Glancing Angle ◽

Glad Technique ◽

Relative Errors

In this paper, we describe the device developed to control the deposition parameters to manage the glancing angle deposition (GLAD) process of metal-oxide thin films for gas-sensing applications. The GLAD technique is based on a set of parameters such as the tilt, rotation, and substrate temperature. All parameters are crucial to control the deposition of nanostructured thin films. Therefore, the developed GLAD controller enables the control of all parameters by the scientist during the deposition. Additionally, commercially available vacuum components were used, including a three-axis manipulator. High-precision readings were tested, where the relative errors calculated using the parameters provided by the manufacturer were 1.5% and 1.9% for left and right directions, respectively. However, thanks to the formula developed by our team, the values were decreased to 0.8% and 0.69%, respectively.

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Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

International Journal of Nanoscience ◽

10.1142/s0219581x15500118 ◽

2015 ◽

Vol 14 (04) ◽

pp. 1550011 ◽

Cited By ~ 8

Author(s):

A. Sharma ◽

M. Tomar ◽

V. Gupta ◽

A. Badola ◽

N. Goswami

Keyword(s):

Thin Films ◽

Gas Sensing ◽

High Sensitivity ◽

Morphological Properties ◽

X Ray Diffraction ◽

Chemical Route ◽

Sensing Properties ◽

Response Recovery ◽

Transmission Electron ◽

Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

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Preparation and Gas-Sensing Property of Coppertetra-Iso-Propoxyphthalocyanine Spin-Coating Film

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.197-198.1735 ◽

2011 ◽

Vol 197-198 ◽

pp. 1735-1738

Author(s):

Qiang Li ◽

Li Hua Huo ◽

Shan Gao ◽

Xiao Juan Qi ◽

Hui Zhao

Keyword(s):

Thin Films ◽

Spin Coating ◽

Gas Sensing ◽

High Sensitivity ◽

Coating Film ◽

Gas Sensing Properties ◽

Response And Recovery ◽

Ft Ir ◽

Spinning Speed ◽

Spectroscopy Property

The thin films of copper 2, 9, 16, 23-tetra-iso-propoxy phthalocyanine (i-pro-CuPc) were prepared by spin-coating technique. The surface morphology and spectroscopy property of the thin films were characterized by AFM, UV-Vis and FT-IR spectra. The results show that good films can be obtained under certain spinning speed. The gas-sensing properties of the multilayers to three alcohols gas were measured at room temperature. The spin-coating thin films exhibited high sensitivity and rapid response- recovery characteristics to these gases. The response and recovery time of the thin films to 30*10-6 v/v of C2H5OH vapor is only 28 s and 55 s, respectively.

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Deposition of Low-Stress Encapsulants on InP and GaAs

MRS Proceedings ◽

10.1557/proc-75-691 ◽

1986 ◽

Vol 75 ◽

Author(s):

U. K. Chakrabarti ◽

S. J. Pearton ◽

H. Barz ◽

A. R. Vonneida ◽

K. T. Short ◽

...

Keyword(s):

Elevated Temperatures ◽

Secondary Ion Mass Spectrometry ◽

Surface Region ◽

Near Surface ◽

Deposition Parameters ◽

Direct Measurements ◽

Dopant Redistribution ◽

Doped Glass ◽

Phosphorus Doped ◽

Secondary Ion

AbstractAℓN deposited by D.C. triode sputtering and spin-on, phosphorus-doped glass (PSG) layers on GaAs and InP were investigated as encapsulants. These films have similar expansion coefficients to both GaAs and InP, minimizing the amount of strain induced in the near-surface region of the underlying wafer. We have quantified this effect by direct measurements of the stress in the films and by using secondary ion mass spectrometry profiling to measure the redistribution of Cr and Fe in encapsulated GaAs and InP respectively during high temperature processing. The dopant redistribution is considerably less for the AℓN and PSG films compared to the more conventional SiO2 and Si3N4 layers. The interaction of the films with the substrate at elevated temperatures is minimal as determined by Auger profiling and the electrical properties of the surface after removal of the encapsulants. The composition of the films remains essentially constant after annealing, as measured by Rutherford backscattering, and the thickness uniformity over large wafer diameters (2″) can be excellent with close control of the deposition parameters. The activation characteristics of low dose, Si-implanted layers in GaAs using either PSG or AℓN are comparable to those obtained using capless annealing or SiO2 or Si3N4 encapsulation.

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Zinc Self-Diffusion in Isotopic Heterostructured Zinc Oxide Thin Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.421-422.193 ◽

2009 ◽

Vol 421-422 ◽

pp. 193-196 ◽

Cited By ~ 2

Author(s):

Kenji Matsumoto ◽

Yutaka Adachi ◽

Takeshi Ohgaki ◽

Isao Sakaguchi ◽

Tsubasa Nakagawa ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Zinc Oxide ◽

Secondary Ion Mass Spectrometry ◽

Outer Region ◽

Pulsed Laser ◽

Diffusion Annealing ◽

Oxide Thin Films ◽

Near Surface ◽

Zinc Isotopes

Zinc isotopic heterostructured zinc oxide thin films of 64ZnO/68ZnO/64ZnO were synthesized using pulsed laser deposition. The pulsed laser was first irradiated onto a polycrystalline target of 64ZnO to deposit the 64ZnO layer, then onto the 68ZnO target to prepare the 68ZnO layer and finally, the 64ZnO target was used again. The 64ZnO/68ZnO/64ZnO layered thin film was thus obtained. The thin films were annealed at various diffusion annealing temperatures. Diffusion profiles of the zinc isotopes due to the annealing were evaluated using secondary ion mass spectrometry (SIMS). The diffusion coefficients were slightly higher near the interface between the thin film and the substrate (the inner region) compared to the near surface (the outer region).

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Correction Method for Ion Yield Transients in the Near Surface Region of Sims Depth Profiles

MRS Proceedings ◽

10.1557/proc-54-705 ◽

1985 ◽

Vol 54 ◽

Author(s):

S. R. Bryan ◽

R. W. Linton ◽

D. P. Griffis

Keyword(s):

Steady State ◽

Secondary Ion Mass Spectrometry ◽

High Sensitivity ◽

Depth Resolution ◽

Surface Region ◽

Correction Method ◽

Ion Concentration ◽

Near Surface ◽

Ion Yields ◽

Secondary Ion

As solid state device features continue to decrease in size, it has become more important to characterize dopant concentrations within the first several hundred angstroms of the surface. Secondary ion mass spectrometry (SIMS) is the technique of choice for dopant depth profiling due to its high sensitivity and good depth resolution. In order to increase the sensitivity of SIMS, electropositive elements (e.g. oxygen) or electronegative elements (e.g. cesium) are used as primary ion species to enhance positive or negative secondary ion yields, respectively. This has the disadvantage, however, of causing secondary ion yields to vary by up to several orders of magnitude over the first few hundred angstroms of a depth profile as the implanted primary ion concentration increases [1,2]. Secondary ion yields stabilize once the primary ion reaches a steady state concentration, which occurs at a depth proportional to the range of the primary ions in the solid. This ion yield transient artifact hinders quantification of dopant concentrations until the primary ion concentration reaches steady state.

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Surface plasmon assisted toxic chemical NO<sub>2</sub> gas sensor by Au ∕ ZnO functional thin films

Journal of Sensors and Sensor Systems ◽

10.5194/jsss-10-163-2021 ◽

2021 ◽

Vol 10 (2) ◽

pp. 163-169

Author(s):

Ravinder Gaur ◽

Himanshu Mohan Padhy ◽

Manikandan Elayaperumal

Keyword(s):

Thin Film ◽

Thin Films ◽

Optical Properties ◽

Surface Plasmon ◽

Gas Sensing ◽

Low Cost ◽

High Sensitivity ◽

Film Material ◽

Hybrid Thin Film ◽

Spr Sensor

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.

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