Hydrogen sensing performances of Pt/i-ZnO/GaN metal-insulator-semiconductor diodes

作者：Lee Hsin Ying; Huang Hung Lin; Lee Ching Ting^*

来源：Sensors and Actuators B: Chemical , 2011, 157(2): 460-465.

DOI：10.1016/j.snb.2011.05.001

• Hydrogen gas sensors
• GaN
• Intrinsic ZnO layer
• Metal-insulator-semiconductor structure
• Vapor cooling condensation system

In light of the same wurtzite structure and the similar lattice constant and band gap energy between ZnO and GaN-based semiconductors, a high quality intrinsic ZnO film is used as the insulating layer for the Pt/i-ZnO/GaN metal-insulator-semiconductor (MIS) hydrogen gas sensors. When the MIS hydrogen gas sensors are exposed to dilute hydrogen ambience, hydrogen dipoles are formed at the Pt/i-ZnO interface with electrons released back to the ZnO. The hydrogen adsorbed reaction leads to the reduction of the barrier height and the series resistance. When the Pt/i-ZnO(10 nm)/GaN hydrogen gas sensors are exposed to 10,000 ppm H(2) at a room temperature, the resultant barrier height change is 211.9 meV and the series resistance is reduced from 21.4 k Omega to 13.4 k Omega. When the operation temperature increases to 500 K, the corresponding barrier height change is 124.5 meV while the series resistance reduces from 2.5 k Omega to 2.3 k Omega. The hydrogen absorption enthalpy at the interface is about -11.8 kJ/mol, which is the characteristic of exothermic reaction.

• 出版日期2011-10-20