Lan Haihui, Li Yiling, Liu Jinglu, Hu Wenchao, Zhu Xiaohui, Ma Yuxin, Niu Lixin, Zhang Zehao, Jia Shuangfeng, Li Linyang, Chen Yunxu, Wang Jianbo, Zeng Mengqi, Fu Lei
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China.
The Institute for Advanced Studies (IAS), Wuhan University, Wuhan, 430072, China.
Small. 2022 Mar;18(9):e2106341. doi: 10.1002/smll.202106341. Epub 2021 Dec 15.
Germanium, the prime applied semiconductor, is widely used in solid-state electronics and photoelectronics. Unfortunately, since the 3D diamond-like structure with strong covalent bonds impedes the 2D anisotropic growth, only the examples of ultrathin Ge along the (111) plane have been investigated, much less to the controllable synthesis along another crystal surface. Meanwhile, Ge(111) flakes are limited in semiconductor applications because of their gapless property. Here, ultrathin Ge(110) single crystal is synthesized with semiconductive property via gallium-associated self-limiting growth. The obtained ultrathin Ge(110) single crystal exhibits anisotropic honeycomb structure, uniformly incremental lattice, wide tunable direct-bandgap, blue-shifted photoluminescence emission, and unique phonon modes, which are consistent with the previous theoretical predictions. It also confirms excellent second harmonic generation and high hole mobility of 724 cm V s . The realization of ultrathin Ge(110) single crystal will provide an excellent candidate for application in electronics and optoelectronics.
锗作为主要应用的半导体，广泛应用于固态电子学和光电子学领域。不幸的是，由于具有强共价键的三维类金刚石结构阻碍了二维各向异性生长，目前仅对沿（111）面的超薄锗进行了研究，而沿其他晶体表面的可控合成研究则少得多。同时，锗（111）薄片由于其无带隙特性，在半导体应用中受到限制。在此，通过镓相关的自限生长合成了具有半导体特性的超薄锗（110）单晶。所获得的超薄锗（110）单晶呈现出各向异性的蜂窝状结构、均匀递增的晶格、宽可调直接带隙、蓝移光致发光发射以及独特的声子模式，这些与先前的理论预测一致。它还证实了优异的二次谐波产生以及724 cm V s的高空穴迁移率。超薄锗（110）单晶的实现将为电子学和光电子学应用提供一个极佳的候选材料。
