Magnetotransport studies of AlGaN/GaN heterostructures with two-dimensional electron gas in parallel with a three-dimensional Al-graded layer: Incorrect hole type determination - Archive ouverte HAL Access content directly
Journal Articles Journal of Applied Physics Year : 2013

Magnetotransport studies of AlGaN/GaN heterostructures with two-dimensional electron gas in parallel with a three-dimensional Al-graded layer: Incorrect hole type determination

Abstract

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.
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Dates and versions

hal-01208523 , version 1 (02-10-2015)

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Wilfried Desrat, Sylvie Contreras, Leszek Konczewicz, Benoit Jouault, M. Chmielowska, et al.. Magnetotransport studies of AlGaN/GaN heterostructures with two-dimensional electron gas in parallel with a three-dimensional Al-graded layer: Incorrect hole type determination. Journal of Applied Physics, 2013, 114 (2), pp.023704. ⟨10.1063/1.4813220⟩. ⟨hal-01208523⟩
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