Two-dimensional electron gas at the AlGaN/GaN interface: Layer thickness dependence
Two-dimensional electron gas at the AlGaN/GaN interface: Layer thickness dependence
复制标题
AlGaN/GaN 界面处的二维电子气：层厚度依赖性
DOI：
10.1063/1.5142766
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发表时间：
2020
影响因子：
3.2
通讯作者：
K. Pedersen
中科院分区：
文献类型：
--
作者：
V. Popok;P. Caban;P. Michałowski;R. Thorpe;L. Feldman;K. Pedersen
本文研究了AlGaN/GaN界面的结构和性能，解释了AlGaN层厚度对二维电子气（2DEG）形成的影响。我们发现，连续电子气体的生成需要具有稳定化学计量的AlGaN膜，而这种膜只能达到一定的临界厚度，在我们的例子中是≈6-7 nm （20 at）。%铝含量)。较薄的薄膜受到氧化的显著影响，氧化会导致成分变化和结构缺陷，从而导致极化场的不均匀性，从而影响界面上的电子密度。使用开尔文探针力显微镜，这种不均匀性可以可视化为亚微米尺度上表面电位的变化。对于层厚高于临界值的异质结构，表面电位图变得均匀，反映了氧化对界面电子性能的影响减弱。对这些异质结构的霍尔测量证实了2DEG形成。
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.
影响因子：
4.9
作者：
R. Brown;D. Macfarlane;A. Al-Khalidi;Xu Li;G. Ternent;Haiping Zhou;I. Thayne;E. Wasige
通讯作者：
R. Brown;D. Macfarlane;A. Al-Khalidi;Xu Li;G. Ternent;Haiping Zhou;I. Thayne;E. Wasige