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A study of the photoelectrochemical etching of n-GaN in H3PO4 and KOH electrolytes

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Show simple item record Heffernan, Claire Lynch, R.P. Buckley, D.N. 2019-09-24T09:02:20Z 2019-09-24T09:02:20Z 2019
dc.description peer-reviewed en_US
dc.description.abstract We investigated the photoelectrochemical etching of n-GaN in H3PO4 and KOH as a function of electrolyte concentration, potential and light intensity. Etch rates measured by stylus profilometry were compared with coulometric and amperometric values. In both electrolytes, etch rates increased with concentration, reaching a maximum at 3.0 mol dm−3 and decreasing at higher concentrations.The increase in etch rate with concentration of either H3PO4 or KOH reflects the amphoteric nature of gallium and the decrease above 3.0 mol dm−3 is attributed to common-ion effects. Profilometric etch rates were lower than coulometric and amperometric etch rates reflecting formation of a surface film. SEM and profilometry demonstrated that thick surface films are formed at lower concentrations. Etch rates increased linearly with light intensity indicating a carrier-limited etching regime: a quantum efficiency of 57.6% was obtained. At light intensities greater than ∼35 mW cm−2 the etch rates showed evidence of saturation. AFM and SEM images of the etched GaN surfaces showed a distinctive ridge-trench structure with a hexagonal appearance. Photoluminescence spectra of the etched GaN show a significant increase in the defect-related yellow luminescence peak suggesting correlation to the formation of the ridge structures, which may represent dislocations terminating at the surface en_US
dc.language.iso eng en_US
dc.publisher Electrochemical Society en_US
dc.relation.ispartofseries ECS Journal of Solid State Science and Technology;2020 9, 015003
dc.subject GaN samples en_US
dc.subject Sloan Dektak stylus en_US
dc.subject electrolyte en_US
dc.title A study of the photoelectrochemical etching of n-GaN in H3PO4 and KOH electrolytes en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.identifier.doi 10.1149/2.0082001JSS
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US

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