Two-dimensional electron gas at the AlGaN/GaN interface: Layer thickness dependence

Vladimir Popok, Piotr Caban, Pawel Piotr Michalowski, Ryan Thorpe, Leonard Feldman, Kjeld Pedersen

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

2 Citationer (Scopus)
39 Downloads (Pure)


In the current paper, the structure and properties of AlGaN/GaN interfaces are studied, explaining the role of AlGaN layer thickness on the
two-dimensional electron gas (2DEG) formation. It is found that the generation of a continuous electron gas requires AlGaN films with
stable stoichiometry, which can be reached only above a certain critical thickness, ≈6–7 nm in our case (20 at. % Al content). Thinner films
are significantly affected by oxidation, which causes composition variations and structural imperfections leading to an inhomogeneity of the
polarization field and, as a consequence, of the electron density across the interface. Using Kelvin probe force microscopy, this inhomogeneity
can be visualized as variations of the surface potential on the sub-micrometer scale. For heterostructures with layer thickness above the
critical value, the surface potential maps become homogeneous, reflecting a weakening influence of the oxidation on the interface electronic
properties. The 2DEG formation is confirmed by the Hall measurements for these heterostructures
TidsskriftJournal of Applied Physics
Udgave nummer11
Antal sider7
StatusUdgivet - mar. 2020


Dyk ned i forskningsemnerne om 'Two-dimensional electron gas at the AlGaN/GaN interface: Layer thickness dependence'. Sammen danner de et unikt fingeraftryk.