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International Journal of Thin Film Science and Technology

International Journal of Thin Film Science and Technology

Abstract

GaN thin films were synthesized on n-Si (111) and n-Si (100) substrates using a low-cost electrochemical deposition technique for hydrogen gas sensing. SEM images revealed that the grown GaN films consist of a network of nanoflake structures. XRD analyses showed both the hexagonal wurtzite and the cubic zinc blend GaN phases for the deposited films with the crystallite size around 18-19 nm. Photoluminescence spectrum showed that the energy gaps of h-GaN and c-GaN were near 3.39eV and 3.2eV respectively at 300K. Corresponding I-V characteristics of the Schottky diodes were recorded before and after hydrogen gas exposure. Thermionic emission model was used to analyses I-V data. The barrier height increased significantly with hydrogen flow rate. Sensitivity and response time were discussed for the two samples.

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