Zou Xiaobin, Tian Fei, Liang Haikuan, Li Yan, Sun Yong, Wang Chengxin
State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, People's Republic of China.
ACS Nano. 2022 Nov 22;16(11):19543-19550. doi: 10.1021/acsnano.2c09997. Epub 2022 Nov 9.
Characteristics like air-stability and high carrier mobility make non-van-der-Waals layered BiOSe a good prospect for planar integrated nanosystems. However, experimental investigation about its analogue BiOTe is rather rare due to difficulty in synthesis. Herein, a low-pressure CVD process is proposed that is adjusted to the rigorous growth condition required, with large-scale BiOTe ultrathin film obtained. Magneto-transport behavior reveals a very large anisotropic nonsaturating low-temperature magnetoresistance (∼1133% under 9 T magnetic field). Despite the contradiction between high conductivity and ferroelectricity in principle (mobile electrons screen electrostatic forces between ions), the high-conductive BiOTe film here is revealed experimentally as another intrinsic ferroelectric with the polarization switchable by external electric field (predicted in , 17, 6309). These results prove that BiOTe possesses a very narrow bandgap (∼0.15 eV), high conductivity, large magnetoresistance, and room-temperature ferroelectricity, displaying great potential as a high-performance nanoelectronic two-dimensional semiconductor and, in advanced functional devices, working in the mid-infrared region.
诸如空气稳定性和高载流子迁移率等特性，使得非范德瓦尔斯层状BiOSe在平面集成纳米系统方面具有良好的应用前景。然而，由于合成困难，关于其类似物BiOTe的实验研究相当罕见。在此，我们提出了一种低压化学气相沉积工艺，该工艺针对所需的严格生长条件进行了调整，从而获得了大规模的BiOTe超薄膜。磁输运行为揭示了一种非常大的各向异性非饱和低温磁电阻（在9 T磁场下约为1133%）。尽管原则上高电导率和铁电性之间存在矛盾（移动电子屏蔽离子之间的静电力），但这里的高导电BiOTe薄膜在实验中被揭示为另一种本征铁电体，其极化可通过外部电场切换（在文献[具体文献]，17, 6309中有预测）。这些结果证明，BiOTe具有非常窄的带隙（约0.15 eV）、高电导率、大磁电阻和室温铁电性，在作为高性能纳米电子二维半导体以及在先进功能器件中工作于中红外区域方面显示出巨大潜力。
