TY - JOUR
T1 - Enhancement of NO2 sensing properties of In2O3-based thin films using an Au or Ti surface modification
AU - Steffes, H.
AU - Imawan, C.
AU - Solzbacher, F.
AU - Obermeier, E.
N1 - Funding Information:
The authors would like to thank Dr. P. Fricke at the Institute Fresenius, Dresden for performing WDX and XRD measurements. Financial support through the German Ministry of Education and Research BMBF is gratefully acknowledged.
PY - 2001/8/30
Y1 - 2001/8/30
N2 - Metal oxide gas sensors using In2O3 are able to detect low concentrations of NO2. The gas sensitive properties of In2O3 can be improved by adding catalysts or promoters. In the present work, the surface modification of reactively RF-sputtered In2O3 films (cubic phase) using Ti or Au is presented. The surface modified In2O3 films are investigated with respect to physical and gas sensitive properties. Fine distributed Au particles can be formed on top of the In2O3 surface. This enhances the NO2 sensitivity significantly by a factor of 9 at 350°C and by a factor of 3.6 at 400°C. A low cross-sensitivity toward several gases, such as SO2, NH3, CO and H2, is found. The response time τ50 at 400°C is decreased from 4.0 to 2.2 min. On the other hand, particles of amorphous TiO2 can be produced on top of the In2O3 surface. The Ti additive improves the signal shape of the response toward traces of NO2. The response time τ50 at 400°C is decreased from 4.0 to 1.8 min. For the Au surface modification a possible sensing mechanism is discussed.
AB - Metal oxide gas sensors using In2O3 are able to detect low concentrations of NO2. The gas sensitive properties of In2O3 can be improved by adding catalysts or promoters. In the present work, the surface modification of reactively RF-sputtered In2O3 films (cubic phase) using Ti or Au is presented. The surface modified In2O3 films are investigated with respect to physical and gas sensitive properties. Fine distributed Au particles can be formed on top of the In2O3 surface. This enhances the NO2 sensitivity significantly by a factor of 9 at 350°C and by a factor of 3.6 at 400°C. A low cross-sensitivity toward several gases, such as SO2, NH3, CO and H2, is found. The response time τ50 at 400°C is decreased from 4.0 to 2.2 min. On the other hand, particles of amorphous TiO2 can be produced on top of the In2O3 surface. The Ti additive improves the signal shape of the response toward traces of NO2. The response time τ50 at 400°C is decreased from 4.0 to 1.8 min. For the Au surface modification a possible sensing mechanism is discussed.
KW - Au
KW - InO thin films
KW - NO sensor
KW - Surface modification
KW - TiO
UR - http://www.scopus.com/inward/record.url?scp=0035975013&partnerID=8YFLogxK
U2 - 10.1016/S0925-4005(01)00799-7
DO - 10.1016/S0925-4005(01)00799-7
M3 - Article
AN - SCOPUS:0035975013
VL - 78
SP - 106
EP - 112
JO - Sensors and Actuators B: Chemical
JF - Sensors and Actuators B: Chemical
SN - 0925-4005
IS - 1-3
ER -