Experimental Evidence of Large Bandgap Energy in Atomically Thin AlN
Experimental Evidence of Large Bandgap Energy in Atomically Thin AlN
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原子薄 AlN 中大带隙能量的实验证据
DOI：
10.1002/adfm.201902608
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发表时间：
2019
影响因子：
19
通讯作者：
Wang Xinqian
中科院分区：
文献类型：
--
作者：
Wang Ping;Wang Tao;Wang Hui;Sun Xiaoxiao;Huang Pu;Sheng Bowen;Rong Xin;Zheng Xiantong;Chen Zhaoying;Wang Yixin;Wang Ding;Liu Huapeng;Liu Fang;Yang Liuyun;Li Duo;Chen Ling;Yang Xuelin;Xu Fujun;Qin Zhixin;Shi Junjie;Yu Tongjun;Ge Weikun;Shen Bo;Wang Xinqian
BN以外的超薄III族氮化物，如GaN和AlN，由于其在2D光电器件中的潜在应用而吸引了许多研究兴趣。利用原子厚度，由于量子限制，这些薄膜的带隙有望加宽。AlN自支撑结构作为一种很有前途的本征介电层和隧穿层，其能带结构还停留在理论描述上，尚未得到系统的研究。在这项工作中，原子级薄的六方AlN纳米管的壁厚可控已通过选择性热蒸发的GaN/AlN核/壳纳米线，其中的GaN核完全分解，并从底部开口端被删除，而强大的AlN壳仍然存在，形成管状结构。通过对具有两个单层壁厚的AlN纳米管的光谱分辨X射线光电子能谱和空间分辨电子能量损失谱测量，确认带隙能量为9.2±0.1 eV。
Ultrathin III‐nitrides beyond BN, such as GaN and AlN, have attracted much research interest due to their potential applications in 2D optoelectronic devices. Taking advantage of the atomic thickness, the bandgap is expected to be widened in these thin films due to quantum confinement. As a promising intrinsic dielectric and tunneling layer for optoelectronic devices, ultrathin freestanding AlN structures have not been systematically studied, and the band structure still remains in the theoretical description. In this work, atomically thin hexagonal AlN nanotubes with controllable wall thickness have been fabricated via selective thermal evaporating the GaN/AlN core/shell nanowires, where the GaN cores entirely decomposed and are removed from the bottom open end while the robust AlN shells remain and form tubular structures. The bandgap energy of 9.2±0.1 eV is confirmed through spectrally resolved X‐ray photoelectron spectroscopy and spatially resolved electron energy loss spectroscopy measurements on AlN nanotubes with the wall thickness of two monolayers.