The GaN(0001) yellow-luminescence-related surface state and its interaction with air

Yury Turkulets, Nitzan Shauloff, Or Haim Chaulker, Yoram Shapira, Raz Jelinek, Ilan Shalish*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Yellow luminescence (YL) is probably the longest and most studied defect-related luminescence band in GaN, yet its electronic structure or chemical identity remain unclear. Most of the theoretical work so far has attributed the feature to bulk defects, whereas spectroscopic studies have suggested a surface origin. Here, we apply deep level spectroscopy using sub-bandgap surface photovoltage that provides the energy distribution of the surface charge density. Comparison of surface charge spectra obtained under identical conditions before and after various surface treatments reveals the dynamics of the surface charge density. Further comparison with spectra of the entire state obtained using photoluminescence shows how the charge density stored in YL-related defects is eliminated upon a mild anneal in vacuum. This suggests that the YL-related defect involves a certain molecule adsorbed on the GaN surface, possibly in a complex with an intrinsic surface defect. The observed interaction with air strongly indicates that the YL-related deep level is a surface state.

Original languageEnglish
Article number102834
JournalSurfaces and Interfaces
Volume38
DOIs
StatePublished - Jun 2023

Keywords

  • Adsorption
  • Current collapse
  • Deep levels
  • Defects
  • Desorption
  • GaN
  • High electron mobility transistor
  • Interface states
  • Surface States
  • Surface charge density
  • Surface photovoltage spectroscopy
  • Traps
  • Vacuum anneal
  • Yellow luminescence

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