Field-effect conductivity scaling for two-dimensional materials with tunable impurity density
Field-effect conductivity scaling for two-dimensional materials with tunable impurity density
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DOI：
10.1088/2053-1583/ac72b0
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发表时间：
2022-05
期刊：
影响因子：
5.5
通讯作者：
Chulin Wang;Lintao Peng;Spencer A. Wells;Jeffrey D. Cain;Yi-Kai Huang;Lawrence A Rhoads;V. Dravid;M. Hersam;M. Grayson
中科院分区：
文献类型：
--
作者：
Chulin Wang;Lintao Peng;Spencer A. Wells;Jeffrey D. Cain;Yi-Kai Huang;Lawrence A Rhoads;V. Dravid;M. Hersam;M. Grayson
在具有可调电离杂质散射体浓度的门控二维（2D）材料的电导率中证明了标度定律。实验数据显示，当迁移率按r缩放时，相对杂质诱导的散射，以及杂质诱导的掺杂导致的栅极电压移动v时，实验数据崩溃到单个二维电导率缩放（2DCS）曲线上。该2DCS分析首先在T=100K的封装2D黑磷多层膜中进行演示，其电荷阱密度在冷却时由栅极偏置编程，然后在室温下暴露于不同浓度的气体吸附剂中的Bi2Se3 2D单层中进行演示。观察到的结垢现象可以用屏蔽的电离杂质散射体的电导率模型来解释。r Vs图的斜率定义了无序电荷比散射率Γq=dr/dVs，相当于单位杂质电荷密度的散射强度：Γq>0表示带正电的杂质占优势，带负电的杂质Γq<0。这种2DCS分析有望适用于任意具有可调杂质密度的二维材料体系，这将推进二维材料的表征并提高二维传感器和晶体管的性能。
A scaling law is demonstrated in the conductivity of gated two-dimensional (2D) materials with tunable concentrations of ionized impurity scatterers. Experimental data is shown to collapse onto a single 2D conductivity scaling (2DCS) curve when the mobility is scaled by r, the relative impurity-induced scattering, and the gate voltage is shifted by Vs , a consequence of impurity-induced doping. This 2DCS analysis is demonstrated first in an encapsulated 2D black phosphorus multilayer at T=100K with charge trap densities programmed by a gate bias upon cooldown, and next in a Bi2Se3 2D monolayer at room temperature exposed to varying concentrations of gas adsorbates. The observed scaling can be explained using a conductivity model with screened ionized impurity scatterers. The slope of the r vs. Vs plot defines a disorder-charge specific scattering rate Γq=dr/dVs equivalent to a scattering strength per unit impurity charge density: Γq>0 indicates a preponderance of positively charged impurities with Γq<0 for negatively charged. This 2DCS analysis is expected to be applicable in arbitrary 2D materials systems with tunable impurity density, which will advance 2D materials characterization and improve performance of 2D sensors and transistors.