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Title: Microstructure and electrical properties of MgAl[sub 2]O[sub 4] thin films for humidity sensing

Abstract

Active elements for humidity sensors based upon MgAl[sub 2]O[sub 4] thin films or sintered pellets were investigated. Thin films were deposited on Si/SiO[sub 2] substrates by radiofrequency (rf) sputtering. Sintered MgAl[sub 2]O[sub 4] pellets were prepared by traditional ceramic processing. Scanning electron microscopy (SEM) analysis showed that the thin films were rather dense and homogeneous, made up of clustered particles of about 20-30 nm, while the pellets showed a wide pore-size distribution. X-ray photoelectron spectroscopy (XPS) demonstrated that the thin films have a stoichiometry close to that of MgAl[sub 2]O[sub 4]. Sintered MgAl[sub 2]O[sub 4] is crystalline, while it is disordered in thin-film form. The presence of two different components of the Al 2p peaks was correlated with the structural difference between pellets and thin films. The relationship between good film-substrate adhesive properties and the chemical composition at the interface was studied. The electrical properties of the sensing elements were studied at 40C in environments at different relative humidity (RH) values between 2% and 95%, using ac impedance spectroscopy. MgAl[sub 2]O[sub 4] thin films showed interesting characteristics in terms of their use in humidity-measurement devices. Resistance versus RH sensitivity values showed variations as high as 4 orders of magnitude inmore » the RH range tested for thin films, and 5 orders of magnitude for pellets. The differences in the electrical behavior of MgAl[sub 2]O[sub 4] pellets and thin films were correlated with their different microstructures.« less

Authors:
; ;  [1];  [2]
  1. Univ. di Roma Tor Vergata, Rome (Italy). Dept. di Scienze e Tecnologie Chimiche
  2. CNR, Rome (Italy). Inst. di Teroria e Struttura Electronica
Publication Date:
OSTI Identifier:
6301516
Resource Type:
Journal Article
Journal Name:
Journal of the American Ceramic Society; (United States)
Additional Journal Information:
Journal Volume: 76:3; Journal ID: ISSN 0002-7820
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM OXIDES; ELECTRICAL PROPERTIES; MICROSTRUCTURE; MAGNESIUM OXIDES; COMPARATIVE EVALUATIONS; ELECTRIC CONDUCTIVITY; ELECTRIC IMPEDANCE; EXPERIMENTAL DATA; MOISTURE GAGES; PELLETS; PHOTOELECTRON SPECTROSCOPY; POROSITY; SAMPLE PREPARATION; SCANNING ELECTRON MICROSCOPY; SILICON; SILICON OXIDES; SINTERING; SPECTROSCOPY; SPUTTERING; STOICHIOMETRY; SUBSTRATES; THIN FILMS; X-RAY SPECTROSCOPY; ALKALINE EARTH METAL COMPOUNDS; ALUMINIUM COMPOUNDS; CHALCOGENIDES; DATA; ELECTRON MICROSCOPY; ELECTRON SPECTROSCOPY; ELEMENTS; EVALUATION; FABRICATION; FILMS; IMPEDANCE; INFORMATION; MAGNESIUM COMPOUNDS; MEASURING INSTRUMENTS; MICROSCOPY; NUMERICAL DATA; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; SEMIMETALS; SILICON COMPOUNDS; 360202* - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 360204 - Ceramics, Cermets, & Refractories- Physical Properties

Citation Formats

Gusmano, G, Montesperelli, G, Traversa, E, and Mattogno, G. Microstructure and electrical properties of MgAl[sub 2]O[sub 4] thin films for humidity sensing. United States: N. p., 1993. Web. doi:10.1111/j.1151-2916.1993.tb03669.x.
Gusmano, G, Montesperelli, G, Traversa, E, & Mattogno, G. Microstructure and electrical properties of MgAl[sub 2]O[sub 4] thin films for humidity sensing. United States. https://doi.org/10.1111/j.1151-2916.1993.tb03669.x
Gusmano, G, Montesperelli, G, Traversa, E, and Mattogno, G. 1993. "Microstructure and electrical properties of MgAl[sub 2]O[sub 4] thin films for humidity sensing". United States. https://doi.org/10.1111/j.1151-2916.1993.tb03669.x.
@article{osti_6301516,
title = {Microstructure and electrical properties of MgAl[sub 2]O[sub 4] thin films for humidity sensing},
author = {Gusmano, G and Montesperelli, G and Traversa, E and Mattogno, G},
abstractNote = {Active elements for humidity sensors based upon MgAl[sub 2]O[sub 4] thin films or sintered pellets were investigated. Thin films were deposited on Si/SiO[sub 2] substrates by radiofrequency (rf) sputtering. Sintered MgAl[sub 2]O[sub 4] pellets were prepared by traditional ceramic processing. Scanning electron microscopy (SEM) analysis showed that the thin films were rather dense and homogeneous, made up of clustered particles of about 20-30 nm, while the pellets showed a wide pore-size distribution. X-ray photoelectron spectroscopy (XPS) demonstrated that the thin films have a stoichiometry close to that of MgAl[sub 2]O[sub 4]. Sintered MgAl[sub 2]O[sub 4] is crystalline, while it is disordered in thin-film form. The presence of two different components of the Al 2p peaks was correlated with the structural difference between pellets and thin films. The relationship between good film-substrate adhesive properties and the chemical composition at the interface was studied. The electrical properties of the sensing elements were studied at 40C in environments at different relative humidity (RH) values between 2% and 95%, using ac impedance spectroscopy. MgAl[sub 2]O[sub 4] thin films showed interesting characteristics in terms of their use in humidity-measurement devices. Resistance versus RH sensitivity values showed variations as high as 4 orders of magnitude in the RH range tested for thin films, and 5 orders of magnitude for pellets. The differences in the electrical behavior of MgAl[sub 2]O[sub 4] pellets and thin films were correlated with their different microstructures.},
doi = {10.1111/j.1151-2916.1993.tb03669.x},
url = {https://www.osti.gov/biblio/6301516}, journal = {Journal of the American Ceramic Society; (United States)},
issn = {0002-7820},
number = ,
volume = 76:3,
place = {United States},
year = {Mon Mar 01 00:00:00 EST 1993},
month = {Mon Mar 01 00:00:00 EST 1993}
}