%0 Journal Article
%T Magnetotransport studies of AlGaN/GaN heterostructures with two-dimensional electron gas in parallel with a three-dimensional Al-graded layer: Incorrect hole type determination
%+ Laboratoire Charles Coulomb (L2C)
%+ Centre de recherche sur l'hétéroepitaxie et ses applications (CRHEA)
%A Desrat, Wilfried
%A Contreras, Sylvie
%A Konczewicz, Leszek
%A Jouault, Benoit
%A Chmielowska, M.
%A Chenot, S.
%A Cordier, Y.
%Z The authors would like to thank Dr. E. Litwin-Staszewska from the Institute of High Pressure Physics “Unipress,” for the Hall bar processing on the 3D electron slab. This work was supported by the GANEX program (ANR-11-LabEx-0014).
%< avec comité de lecture
%Z L2C:13-390
%@ 0021-8979
%J Journal of Applied Physics
%I American Institute of Physics (AIP)
%V 114
%N 2
%P 023704
%8 2013-07-14
%D 2013
%R 10.1063/1.4813220
%Z Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Journal articles
%X We report magnetotransport measurements performed on AlGaN/GaN devices with different buffer layers. Standard samples with a 1 μm thick GaN buffer show a linear Hall resistance and an almost constant magnetoresistance, as expected from a single two-dimensional electron gas (2DEG) at the AlGaN/GaN interface. Other samples, with an Al x Ga1– x N buffer (x = 5%) and a buried linear aluminium gradient, have an additional three-dimensional electron slab (3DES) close to the GaN substrate. In this case, the Hall resistance is strongly non-linear and presents an incorrect hole-type carrier signature, evidenced by low field mobility spectrum analysis. This effect is strengthened when the 3D layer, parallel to the mesa-etched 2DEG, is infinite. We suggest that the misplacement of the electrical contacts in the 3DES, i.e., far from the sample edges, could explain the wrong carrier type determination.
%G English
%L hal-01208523
%U https://hal.science/hal-01208523
%~ UNICE
%~ CNRS
%~ L2C
%~ MIPS
%~ UNIV-MONTPELLIER
%~ UNIV-COTEDAZUR
%~ ANR
%~ CRHEA
%~ UM-2015-2021