Space-charge-limited current in nanowires
Space-charge-limited current in nanowires
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DOI：
10.1063/1.4982222
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发表时间：
2017-05-07
影响因子：
3.2
通讯作者：
Watkins, S. P.
中科院分区：
文献类型：
--
作者：
Alagha, S.;Shik, A.;Watkins, S. P.
由于载流子耗尽和静电屏蔽减少，在半导体纳米线中经常观察到空间电荷限制电流。我们使用 n(+) -n-n(+) 模型，与薄膜和体几何结构进行比较，对纳米线中空间电荷限制电流的几何缩放进行了数值研究。该模型强调了周围环境对薄膜和纳米线的影响，并表明半导体的介电特性对小尺寸的空间电荷限制传输的影响可以忽略不计。平衡分布和注入电荷浓度随着半导体尺寸的减小而变化。对于低掺杂，欧姆电流由简并触点的电荷扩散控制，而不是由纳米线杂质浓度控制。数值计算的结果与简单的电容形式一致，该形式假设沿纳米线的电荷分布均匀，并且 InAs 纳米线的实验测量证实了这些结果。数值模型还预测，不对称纳米线接触几何形状可以增强或限制电荷注入。由 AIP 出版社出版。
Space-charge-limited current is often observed in semiconductor nanowires due to carrier depletion and reduced electrostatic screening. We present a numerical study on geometric scaling of the space-charge-limited current in nanowires, in comparison with the thin film and bulk geometries, using an n(+) -n-n(+) -model. The model highlights the effects of the surroundings for thin films and nanowires and shows that the dielectric properties of the semiconductor have a negligible effect on the space-charge-limited transport for small dimensions. The distribution of equilibrium and injected charge concentration vary as the semiconductor dimensionality is reduced. For low doping, the ohmic current is controlled by charge diffusion from degenerate contacts rather than by the nanowire impurity concentration. The results of numerical calculations agree with a simple capacitance formalism which assumes a uniform charge distribution along the nanowire, and experimental measurements for InAs nanowires confirm these results. The numerical model also predicts that an asymmetric nanowire contact geometry can enhance or limit charge injection. Published by AIP Publishing.