Improved device performance of AlGaInP-based vertical light-emitting diodes with low-n ATO antireflective coating layer

We reported the effect of low-n Sb-doped tin oxide (ATO) antireflective (AR) coating layer on the device performance of AlGaInP-based red vertical light-emitting diodes (VLEDs). The ATO films with a quarter wavelength thickness of ∼90 nm were deposited on the p-GaP window layer by an oblique-angle sputtering method. The ATO films with inclined nanocolumnar structures indicated a low refractive index of ∼1.8 at emitting wavelengths of AlGaInP-based VLEDs. For VLED with low-n ATO AR coating layer, the light output power was increased by 26% at 350 mA with no deterioration of the electrical property compared to the conventional LED. Also, the enhanced light extraction led to the reduction in the electroluminescence peak wavelength shift at higher injection currents.

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► We fabricated the AlGaInP-based VLEDs with low-n ATO antireflective coating layer.
► The low-n ATO films were deposited on the p-GaP window layer of LEDs by an oblique-angle sputtering method.
► The internal reflection was efficiently suppressed by coating the low-n ATO layer.
► The results showed the improved device performances of LEDs.