Interfacial N Vacancies in GaN/(Al,Ga)N/GaN Heterostructures

Vera Prozheeva, Ilja Makkonen, Haoran Li, Stacia Keller, Umesh K. Mishra, Filip Tuomisto

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We show that N-polar GaN/(Al,Ga)N/GaN heterostructures exhibit significant N deficiency at the bottom (Al,Ga)N/GaN interface, and that these N vacancies are responsible for the trapping of holes observed in unoptimized N-polar GaN/(Al,Ga)N/GaN high electron mobility transistors. We arrive at this conclusion by performing positron annihilation experiments on GaN/(Al,Ga)N/GaN heterostructures of both N and Ga polarity, as well as state-of-the-art theoretical calculations of the positron states and positron-electron annihilation signals. We suggest that the occurrence of high interfacial N vacancy concentrations is a universal property of nitride semiconductor heterostructures at net negative polarization interfaces.
Original languageEnglish
Article number044034
Pages (from-to)1-7
Number of pages7
JournalPhysical Review Applied
Issue number4
Publication statusPublished - Mar 2020
MoE publication typeA1 Journal article-refereed

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  • Projects

    CRYSTRAP: Charge traps in crystalline matter for future technologies

    Tuomisto, F., Heikkinen, T., Vancraeyenest, A., Karjalainen, A. & Slotte, J.


    Project: Academy of Finland: Other research funding

    Large-scale electronic structure techniques for advanced materials characterization

    Makkonen, I., Simula, K., Prozheeva, V. & Härkönen, J.


    Project: Academy of Finland: Other research funding



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    School of Science

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