Improving hydrogen detecting performance of a Pd/n-LTPS/glass thin film Schottky diode with a TiO2 interface layer

The hydrogen detecting performance of a Pd/n-LTPS/glass thin film Schottky diode is significantly improved with a TiO2 interface layer. The n-LTPS (n-type low temperature polysilicon) thin film is an amorphous silicon (a-Si) film on a glass substrate with both excimer laser annealing and PH3 gas plasma treating. Under the conditions of room temperature and -2V bias, the addition of the TiO2 interface layer promotes the relative sensitivity ratio from 290.4% to 1539.6% to 50 ppm H-2. The response time is also reduced from 61s to 40s. Compared to the reported H-2 sensors with bulk Si or III-V compounds, the developed Pd/TiO2/n-LTPS/glass Schottky diode shows a high potential in development and realization of a low cost and highly sensitive hydrogen sensor. (c) 2008 Elsevier B.V. All rights reserved.