Three Subband Occupation of the Two-Dimensional Electron Gas in Ultrathin Barrier AlN/GaN Heterostructures
Three Subband Occupation of the Two-Dimensional Electron Gas in Ultrathin Barrier AlN/GaN Heterostructures
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超薄势垒AlN/GaN异质结构中二维电子气的三个子带占据
DOI：
10.1002/adfm.202004450
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发表时间：
2020
影响因子：
19
通讯作者：
Bo Shen
中科院分区：
文献类型：
--
作者：
Liuyun Yang;Xinqiang Wang;Tao Wang;Jingyue Wang;Wenjie Zhang;Patrick Quach;Ping Wang;Fang Liu;Duo Li;Ling Chen;Shangfeng Liu;Jiaqi Wei;Xuelin Yang;Fujun Xu;Ning Tang;Wei Tan;Jian Zhang;Weikun Ge;Xiaosong Wu;Chi Zhang;Bo Shen
通过分子束外延实现了具有82Ωsq−1片电阻的超薄势垒AlN/GaN异质结构，并观察到二维电子气（2DEG）的舒布尼科夫-德哈斯振荡（SdHOs）和量子霍尔效应（QHE）。快速傅里叶变换分析首次证明了三角形量子阱中存在三个子带，电子密度分别为n1=2.2×1013cm−2、n2=2.3×1012cm−2和n3=8.8×1011cm−2，对应能量为265、28和11 meV，低于费米能级。具有叠加特征的三亚带QHE也首次在AlN/GaN异质结构中得到证明，在高电子密度下具有大填充因子。通过分析第一子带作为叠加QHE的主导部分，揭示了特殊磁子带间散射的输运物理。这些结果有助于更好地理解2DEG的量子物理，从而实现AlN/GaN器件的多功能。
Ultrathin barrier AlN/GaN heterostructure with record low sheet resistance of 82Ωsq−1is achieved by molecular beam epitaxy, where Shubnikov‐de Haas oscillations (SdHOs) and quantum Hall effect (QHE) of two‐dimensional electron gas (2DEG) are observed. The fast Fourier transform analysis of the SdHOs demonstrates a three‐subband occupation in the triangle quantum well for the first time, with the electron density ofn1=2.2×1013cm−2,n2=2.3×1012cm−2, andn3=8.8×1011cm−2, respectively, and the corresponding energy of 265, 28, and 11 meV below Fermi level. The three‐subband QHE with a superposed feature is also demonstrated for the first time in AlN/GaN heterostructure, with large filling factors at high electron densities. By analyzing the first subband as the dominant part of the superposed QHE, the transport physics of a special magneto‐intersubband scattering is revealed. These results contribute to a better understanding of the quantum physics for 2DEG, leading to a versatile functionality for AlN/GaN devices.