Hydrogen gas sensors based on PLD grown NiO thin film structures

NiO thin films were grown by pulsed laser deposition on (100)Si substrates at 200 degrees C temperature. The effect of the O-2 pressure during the deposition process on the morphological, electrical and sensing properties of the films has been investigated. AFM images showed that the surface morphology of NiO films can be modified by the oxygen pressure during deposition. Electrical measurements showed that the well-known native p-type conductivity exhibits a conversion from p-type to n-type when the O-2 pressure is reduced. Resistance responses of NiO-thin films towards hydrogen (H-2) flow in air ambient have been measured. NiO thin film p-n homojuctions were then fabricated to investigate the electrical properties of such structures. The p-n homojunctions exhibited the distinct rectifying current-voltage (I-V) characteristics. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.