Applied Physics Express · 2013 · 40 citations · 18 references
EngineeringMaterials EngineeringMaterials ScienceElectronic MaterialsOptical MaterialsSemiconductor MaterialsDopingEtching ProcessesLight-emitting DiodesNanoporous MaterialsOptical Properties Of SemiconductorsSemiconductor Device MaterialsDiffuse ReflectionEtchingGallium Nitride (Gan) MaterialsGallium Nitride Light-emitting DiodesReflectivitySelective EtchingSpectral Reflectance PropertiesSpecular Reflection
A GaN distributed Bragg reflector (DBR) based on nanoporous GaN was fabricated by doping selective electrochemical etching. Twenty-one pairs of undoped-GaN/n-GaN were grown and only n-GaN was converted into a nanoporous layer during the etching. From spectral reflectance measurement, clear stopbands were observed, but the maximum reflectivity was limited to 87% at ∼450 nm in specular reflection geometry. It was attributed to significant scattering in the DBR caused by the non-uniform formation of nanopores. However, the diffuse reflectivity of nanoporous DBR was much higher (∼100%), which could be advantageous for a diffuse reflection mirror in a light-emitting diode.
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