EFFECT OF SENSOR CONFIGURATION FOR LOW TEMPERATURE GAS DETECTION WITH SEMICONDUCTING OXIDES

This work presents the results obtained towards NO2 by using TBE and IDE sensor configurations with the same sensing semiconductor layers. It is known that dopants such as Al3+ or Cr3+ can improves the sensing properties of semiconductor TiO2. Nevertheless, temperatures exceeding 400°C are required for reasonable sensor signal. The use of TBE configuration reduces the operation temperature of these sensors far below 400°C requiring no heater. The schematic of such a TBE electrode system is presented in Fig. 1. The sensors with TBE configuration were fabricated in three steps: firstly, 200 nm thick and 300 μm wide bottom Pt electrodes BE were patterned (via sputtering) on a Al2O3 substrates. The possible sensing mechanism is the matter of discussion in terms of depletion region (LD) and the potential barrier between grains (eVs at grain boundaries)