Allioux Francois-Marie, Han Jialuo, Tang Jianbo, Merhebi Salma, Cai Shengxiang, Tang Junma, Abbasi Roozbeh, Centurion Franco, Mousavi Maedehsadat, Zhang Chengchen, Xie Wanjie, Mayyas Mohannad, Rahim Md Arifur, Ghasemian Mohammad B, Kalantar-Zadeh Kourosh
School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW 2052, Australia.
ACS Appl Mater Interfaces. 2021 Sep 15;13(36):43247-43257. doi: 10.1021/acsami.1c11213. Epub 2021 Aug 30.
Liquid metals and alloys with high-aspect-ratio nanodimensional features are highly sought-after for emerging electronic applications. However, high surface tension, water-like fluidity, and the existence of self-limiting oxides confer specific peculiarities to their characteristics. Here, we introduce a high accuracy nanometric three-dimensional pulling and stretching method to fabricate liquid-metal-based nanotips from room- or near-room-temperature gallium-based alloys. The pulling rate and step size were controlled with a resolution of up to 10 nm and yielded different nanotip morphologies and lengths as a function of the base liquid metal alloy composition and the pulling parameters. The obtained nanotips presented high aspect ratios over lengths of a few microns and apexes between 10 and 100 nm. The liquid metal alloys were found confined within nanotips with about 10 nm apexes when vertically pulled at 100 nm/s. An amorphous gallium oxide skin was shown to cover the surface of the nanotips, while the liquid core was composed of the initial liquid metal alloys. The electrical contact established at the nanotips was characterized under dynamic conditions. The liquid metal nanotips showed an Ohmic resistance when a continuous liquid metal channel was formed, and a controllable semiconductor state corresponding to a heterojunction formed at the junction between the liquid metal phase and the gallium oxide semiconductor skin. The variable threshold voltages of the heterojunction were controlled via stretching of the nanotips with a 10 nm step resolution. The liquid metal nanotips were also used for establishing soft electronic junctions. This novel method of liquid metal nanotip fabrication with Ohmic and semiconducting behaviors will lead to exciting avenues for developing electronic and sensing devices.
具有高纵横比纳米尺寸特征的液态金属和合金在新兴电子应用中备受追捧。然而，高表面张力、似水的流动性以及自限性氧化物的存在赋予了它们独特的特性。在此，我们介绍一种高精度纳米三维拉伸方法，用于从室温或近室温的镓基合金制备液态金属基纳米尖端。拉伸速率和步长的控制分辨率高达10纳米，并根据基础液态金属合金成分和拉伸参数产生不同的纳米尖端形态和长度。所获得的纳米尖端在几微米的长度上具有高纵横比，尖端尺寸在10到100纳米之间。当以100纳米/秒的速度垂直拉伸时，发现液态金属合金被限制在尖端约10纳米的纳米尖端内。结果表明，非晶态氧化镓外皮覆盖在纳米尖端表面，而液芯由初始液态金属合金组成。在动态条件下对纳米尖端建立的电接触进行了表征。当形成连续的液态金属通道时，液态金属纳米尖端表现出欧姆电阻，并且在液态金属相和氧化镓半导体外皮之间的结处形成对应于异质结的可控半导体状态。通过以10纳米步长分辨率拉伸纳米尖端来控制异质结的可变阈值电压。液态金属纳米尖端还用于建立软电子结。这种具有欧姆和半导体行为的液态金属纳米尖端制造新方法将为开发电子和传感设备带来令人兴奋的途径。
