一步法可控减薄和掺杂二维过渡金属硫族化合物（英文）

Controlled one step thinning and doping of twodimensional transition metal dichalcogenides

二维过渡金属硫族化合物(TMDCs)具有超薄结构,且其电学、光学性质对厚度具有很强的依赖性,近年来备受研究者们的广泛关注.如何控制TMDCs的厚度和掺杂,是其未来应用的关键所在.本文提出了一种简单高效的HAuCl4处理方法,实现了TMDCs的一步法可控减薄和掺杂,可以制备出薄层及单层TMDCs,同时实现了对MoS2的可控p型掺杂.本文系统研究了关键实验参数的影响,并基于此提出了金插层辅助减薄和掺杂TMDCs的机理.研究还发现该方法具有普适性,可以实现对多种TMDCs的可控减薄,包括MoSe2,WS2, WSe2.电学测试表明, HAuCl4处理后的MoS2纳米片具有更高的场效应晶体管开关比,其阈值电压向正电压方向偏移.本工作提出的这种控制二维TMDCs材料厚度和掺杂的方法,对其未来在高性能电子和光电器件的应用具有一定参考价值.

Two-dimensional(2 D) transition metal dichalcogenides(TMDCs) have drawn intensive attention due to their ultrathin feature with excellent electrostatic gating capability, and unique thickness-dependent electronic and optical properties. Controlling the thickness and doping of 2 D TMDCs are crucial toward their future applications. Here, we report an effective HAu Cl4 treatment method and achieve simultaneous thinning and doping of various TMDCs in one step. We find that the HAu Cl4 treatment not only thins thick Mo S2 flakes into few layers or even monolayers, but also simultaneously tunes Mo S2 into p-type. The effects of various parameters in the process have been studied systematically,and an Au intercalation assisted thinning and doping mechanism is proposed. Importantly, this method also works for other typical TMDCs, including WS2, Mo Se2 and WSe2,showing good universality. Electrical transport measurements of field-effect transistors(FETs) based on Mo S2 flakes show a big increase of On/Off current ratios(from 102 to 107) after the HAu Cl4 treatment. Meanwhile, the subthreshold voltages of the Mo S2 FETs shift from-60 to +27 V after the HAu Cl4 treatment, with a p-type doping behavior. This study provides an effective and simple method to control the thickness and doping properties of 2 D TMDCs, paving a way for their applications in high performance electronics and optoelectronics.