Title
Dynamics of charge carrier trapping in NO 2 sensors based on ZnO field-effect transistors
Author
Andringa, A.-M.
Vlietstra, N.
Smits, E.C.P.
Spijkman, M.-J.
Gomes, H.L.
Klootwijk, J.H.
Blom, P.W.M.
de Leeuw, D.M.
Publication year
2012
Abstract
Nitrogen dioxide (NO 2) detection with ZnO field-effect transistors is based on charge carrier trapping. Here we investigate the dynamics of charge trapping and recovery as a function of temperature by monitoring the threshold voltage shift. The threshold voltage shifts follow a stretched-exponential time dependence with thermally activated relaxation times. We find an activation energy of 0.1 eV for trapping and 1.2 eV for detrapping. The attempt-to-escape frequency and characteristic temperature have been determined as 1 Hz and 960 K for charge trapping and 10 11 Hz and 750 K for recovery, respectively. Thermally stimulated current measurements confirm the presence of trapped charge carriers with a trap depth of around 1 eV. The obtained functional dependence is used as input for an analytical model that predicts the sensor's temporal behavior. The model is experimentally verified and a real-time sensor has been developed. The perfect agreement between predicted and measured sensor response validates the methodology developed. The analytical description can be used to optimize the driving protocol. By adjusting the operating temperature and the duration of charging and resetting, the response time can be optimized and the sensitivity can be maximized for the desired partial NO 2 pressure window. © 2012 Elsevier B.V. All rights reserved.
Subject
Mechatronics, Mechanics & Materials
HOL - Holst
TS - Technical Sciences
Electronics
Industrial Innovation
Activation energy
Charge carrier trapping
Field-effect transistor
NO 2 sensors
Stretched-exponential
Thermally stimulated current
Threshold voltage shift
Analytical description
Characteristic temperature
Charge carrier trapping
De-trapping
Functional dependence
Nitrogen dioxides
Operating temperature
Pressure window
Real time sensors
Sensor response
Stretched-exponential
Temporal behavior
Thermally activated
Thermally stimulated current
Threshold voltage shifts
Time dependence
Trap depth
ZnO
Activation energy
Charge carriers
Charge trapping
Dynamics
Field effect transistors
Optimization
Sensors
Thermoluminescence
Threshold voltage
Zinc oxide
Nitrogen oxides
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http://resolver.tudelft.nl/uuid:cce91a1f-f8c9-4325-a33d-2d9f5697a9ee
TNO identifier
462984
ISSN
0925-4005
Source
Sensors and Actuators, B: Chemical, 171-172, 1172-1179
Document type
article