High sensitivity hydrogen sensing with Pt-decorated porous gallium nitride prepared by metal-assisted electroless etching.

摘要: A unique hydrogen sensor structure based on Pt-decorated porous gallium nitride (PGaN) was fabricated by a two-step process consisting of metal-assisted electroless etching to produce PGaN with highly anisotropic pores followed deposition Pt in the from an ammoniacal PtCl62− solution. The contains 50–100 nm diameter nanopores which are 400 1 µm deep and filled islands. Both steps done solution allow for large-scale production. An AC four-point probe conductivity measurement implemented at f = kHz, frequency where impedance Pt–PGaN is nearly entirely resistive, change conductance upon H2 exposure measured three sample types: surface sputtered layer only; unetched GaN (CGaN) both electrolessly deposited Pt; Pt. sensing performance Pt-filled more than order magnitude better either other two types under all experimental conditions, observation attributed significant increase Pt–GaN interfacial area decorated samples, exhibiting response concentrations as low ppm. changes ascribed adsorption-induced polarization that band bending thus width space charge region near interface.