1:30 PM - 3:30 PM
△ [7p-PB5-1] Formation and characterization of porous SiC using anodic oxidation with potassium persulfate solution
Keywords:semiconductor, porous SiC, quantum confinement effect
Porous SiC is an interesting material to realize a reliable monolithic pure-white LED combined with fluorescence-SiC. To obtain high quality and high color rendering index (CRI) white emission, it is necessary to control porous structure because the light-emission efficiency and wavelength are greatly dependent the porous structure such as average pore size and porosity by anodic.
In this study, we investigated the formation and characterization of porous SiC using oxidant (K2S2O8) to control porosity of porous SiC. In anodic oxidation, the samples are etched for 16 h under a pulsed current of 1.25 mA (pulsed width of 25ms and repetition period of 50ms) in the HF solution including potassium persulfate. Concentration of K2S2O8 was initially fixed at 0.015 mol/L. In this case, excessive chemical reaction was introduced, and it caused the surface roughness and peering off of the porous layer. Hence, we modified the experimental condition that HF solution was diluted by organic solvent. Resultant porous SiC showed highly porosity but stable without peering off from the substrate, and we observed high PL intensity with a peak wavelength of 370 nm, which is shorter than 408 nm corresponding to the band-edge emission of bulk 6H-SiC. This is the shortest emission wavelength from the 6H-SiC based porous SiC. In addition, the PL intensity was 22 times higher than that of bulk SiC. Through the study of porous SiC we demonstrated that the peak wavelength of the porous SiC could be control from 370 to 500 nm.
Porous SiC created by the anodic oxidation method is proven to have a great potential to realize the high CRI white light generation in LEDs.
In this study, we investigated the formation and characterization of porous SiC using oxidant (K2S2O8) to control porosity of porous SiC. In anodic oxidation, the samples are etched for 16 h under a pulsed current of 1.25 mA (pulsed width of 25ms and repetition period of 50ms) in the HF solution including potassium persulfate. Concentration of K2S2O8 was initially fixed at 0.015 mol/L. In this case, excessive chemical reaction was introduced, and it caused the surface roughness and peering off of the porous layer. Hence, we modified the experimental condition that HF solution was diluted by organic solvent. Resultant porous SiC showed highly porosity but stable without peering off from the substrate, and we observed high PL intensity with a peak wavelength of 370 nm, which is shorter than 408 nm corresponding to the band-edge emission of bulk 6H-SiC. This is the shortest emission wavelength from the 6H-SiC based porous SiC. In addition, the PL intensity was 22 times higher than that of bulk SiC. Through the study of porous SiC we demonstrated that the peak wavelength of the porous SiC could be control from 370 to 500 nm.
Porous SiC created by the anodic oxidation method is proven to have a great potential to realize the high CRI white light generation in LEDs.