Attachable freezing-delayed surfaces for ultraviolet sensing using GaN photodetector at low temperature in air

Hongyun So, Woosung Park

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The enhanced optical sensitivity of gallium nitride (GaN) ultraviolet (UV) photodetectors is demonstrated using attachable and hydrophobic freezing-delayed surfaces. The GaN surface attached to microfabricated surfaces with an array of pyramid structures reduced the surface reflectance compared with that of bare GaN surface (∼43.3% decrease at 365 nm wavelength). In addition, as the operation temperature decreased, the hydrophobic pyramid microstructures prevented rapid frost formation by generating dispersed and small-sized frosts (ice crystals). Consequently, the photodetectors fabricated using hydrophobic surfaces with pyramid microstructures showed higher sensitivity (∼48.5% increase in the temperature range of −14 °C to 0 °C) compared to the photodetectors on bare GaN surfaces, supporting the use of hydrophobic surfaces composed of microstructures for UV sensing with higher sensitivity in low-temperature environments.

Original languageEnglish
Pages (from-to)261-265
Number of pages5
JournalApplied Surface Science
Publication statusPublished - 2019 Apr 15



  • Delayed freezing
  • Frost formation
  • Gallium nitride
  • Pyramidal surface
  • Ultraviolet photodetectors

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