ZnO/La{sub 2}CuO{sub 4} hetero-contacts as humidity sensors

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:28853

Traversa, E; Bianco, A; Montesperelli, G; Gusmano, G ^[1]; Bearzotti, A ^[2]; Miyayama, Masaru; Yanagida, Hiroaki ^[3]

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1. Univ. of Rome (Italy)
2. Institute of Solid State Electronics, Rome (Italy)
3. Univ. of Tokyo (Japan)

The humidity sensitivity of hetero-contacts between p-type La{sub 2}CuO{sub 4} and n-type ZnO semiconductors, and of the single oxides, as a comparison, was studied. Hetero-contacts were prepared by mechanically pressing sintered pellets of the two oxides. The electrical analysis of the hetero-contacts was carried out using d.c. and a.c. measurements at various relative humidity (rh) values, in order to evaluate the sensing mechanism and the electrical properties of these p-n junctions. The current-voltage (I-V) curves were typical of p-n diodes at all rh values. The current versus rh sensitivity of the hetero-contacts was bias-dependent, and at 2.5 V it was as high as 4 orders of magnitude. The capacitance-voltage (C-V) curves showed the presence of a large number of interface states, responsible for the diode behavior. The rh-sensitivity was explained in terms of the variation of the barrier height at the junctions due to the saturation of the original interface states by physisorbed water, which leads to the release of trapped electrons, resulting in an increase in the forward current.

• OSTI ID: 28853
• Report Number(s): CONF-931142--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COPPER OXIDES
DETECTION
ELECTRICAL PROPERTIES
FABRICATION
HETEROJUNCTIONS
HUMIDISTATS
HUMIDITY
LANTHANUM OXIDES
N-TYPE CONDUCTORS
P-TYPE CONDUCTORS
SEMICONDUCTOR DETECTORS
THIN FILMS
ZINC OXIDES