Strain Engineering for Transition Metal Dichalcogenides Based Field Effect Transistors
Strain Engineering for Transition Metal Dichalcogenides Based Field Effect Transistors
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DOI：
10.1021/acsnano.6b01149
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发表时间：
2016-04-01
期刊：
影响因子：
17.1
通讯作者：
Appenzeller, Joerg
中科院分区：
文献类型：
--
作者：
Shen, Tingting;Penumatcha, Ashish V.;Appenzeller, Joerg
使用三端场效应晶体管（FET）的电气特性，我们证明了大量的应变引起的带隙可调的过渡金属二硫属化物（TMD）在符合理论预测和光学实验。在柔性衬底上制造器件，并使用悬臂梁样品保持器对各种多层TMD FET施加单轴拉伸应变。特别是传输特性分析，我们认为，应变下的修改后的设备特性是明确的证据，在WSe 2的带隙减少100毫电子伏，在室温下1.35%的单轴拉伸应变。此外，所获得的器件特性意味着带隙在相对于由源极/漏极接触限定的参考电势的应变下不均匀地收缩。相反，带隙变化仅与WSe 2的导带边缘的变化有关，导致电子的肖特基势垒（SB）降低，而空穴注入到价带中没有任何变化。SB器件特性的模拟来解释这一点，并量化我们的研究结果。最后，我们的实验结果进行了比较与DFT计算下的应变表现出良好的理论预测和实验数据之间的协议。
Using electrical characteristics from three-terminal field-effect transistors (FETs), we demonstrate substantial strain induced band gap tunability in transition metal dichalcogenides (TMDs) in line with theoretical predictions and optical experiments. Devices were fabricated on flexible substrates, and a cantilever sample holder was used to apply uniaxial tensile strain to the various multilayer TMD FETs. Analyzing in particular transfer characteristics, we argue that the modified device characteristics under strain are clear evidence of a band gap reduction of 100 meV in WSe2, under 1.35% uniaxial tensile strain at room temperature. Furthermore, the obtained device characteristics imply that the band gap does not shrink uniformly under strain relative to a reference potential defined by the source/drain contacts. Instead, the band gap change is only related to a change of the conduction band edge of WSe2, resulting in a decrease in the Schottky barrier (SB) for electrons without any change for hole injection into the valence band. Simulations of SB device characteristics are employed to explain this point and to quantify our findings. Last, our experimental results are compared with DFT calculations under strain showing excellent agreement between theoretical predictions and the experimental data presented here.