A study on MIS Schottky diode based hydrogen sensor using La2O3 as gate insulator

In this work, a Metal-Insulator-Semiconductor (MIS) based Schottky-diode hydrogen sensor was fabricated with La2O3 as a gate insulator. The electrical properties (current-voltage characteristics, change in barrier height and sensitivity) and hydrogen sensing performance (dynamic response and response time) were examined from 25 degrees C to 300 degrees C and towards H-2 with different concentrations. The conduction mechanisms were explained in terms of Fowler-Nordheim tunneling (below 120 degrees C) and the Poole-Frenkel effect at temperatures (above 120 degrees C). The results show that at an operating temperature of 260 degrees C, the sensitivity of the device can reach a maximum value of 4.6 with respect to 10,000-ppm hydrogen gas and its response time was 20 s. (C) 2012 Elsevier Ltd. All rights reserved.