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The Study of Pt/porous GaN Schottky Contact for Hydrogen Sensing

This article presents the studies of Pt Schottky contact on porous n-type GaN for hydrogen sensing. Porous GaN was generated by UV assisted electroless chemical etching. Hydrogen sensor was subsequently fabricated by depositing Pt Schottky contacts onto the porous GaN sample. For comparative study; a standard hydrogen sensor was also prepared by depositing Pt Schottky contacts on the as- grown sample using same processing tools and under identical parameters. Hydrogen detection was carried out at room temperature in an enclosed chamber. Pt/porous GaN sensor exhibited a significant change of current upon exposure to 2% H2 in N2 as compared to the standard Pt/GaN sensor. Morphological studies by scanning electron microscopy (SEM) revealed that Pt contact deposited on porous GaN have a very rough surface morphology with pores distributed all over the contact layer. Therefore, the steep increase of current could be attributed to the unique microstructure at porous Pt/porous GaN interface, which allowed higher accumulation of hydrogen and eventually led to stronger effect of the H- induced dipole layer.