Origin of interfacial charges of Al2O3/Si and Al2O3/GaN heterogeneous heterostructures

Chuanju Wang, Feras AlQatari, Vishal Khandelwal, Rongyu Lin, Xiaohang Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Al2O3 is a broadly employed dielectric and significant interfacial charges occur at Al2O3/semiconductor interfaces. However, the charge origin is often unclear that severely impacts device engineering and design. Al2O3/Si and Al2O3/GaN are two of the most common heterogeneous heterostructures (H2s) for many crucial devices including GaN transistors and Si solar cells. While negative charges are extensively observed in Al2O3/Si, positive charges exist in Al2O3/GaN, both of which are not well understood. In this study, we performed in-depth interfacial studies of the Al2O3/Si and Al2O3/GaN H2s to clarify the origin of the interfacial charges. Stoichiometry deviations were found at the interfaces of the two H2s where Al surpasses O for Al2O3/GaN, whereas O dominates at the Al2O3/Si interface. Therefore, we propose that the different interfacial charges are caused by nonstoichiometry atomic ratios of Al2O3 at the interface. The study indicates the important role of the semiconductor surface on the device performance, provide a deep understanding on the origin of interfacial charges at the insulator-semiconductor interfaces.

Original languageEnglish (US)
Article number155099
JournalApplied Surface Science
StatePublished - Jan 15 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • General Physics and Astronomy
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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