Silicon Nanowire Esaki Diodes
Silicon Nanowire Esaki Diodes
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DOI：
10.1021/nl2035964
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发表时间：
2012-02-01
期刊：
影响因子：
10.8
通讯作者：
Riel, Heike
中科院分区：
文献类型：
--
作者：
Schmid, Heinz;Bessire, Cedric;Riel, Heike
我们报道了硅纳米线隧道二极管的制备和表征。采用Au催化气-液-固相生长和n型原位掺杂方法在p型硅衬底上生长了硅纳米线。电学测量显示，Esaki二极管的峰值电流密度为3.6kA/cm(2)，峰谷电流比高达4.3，在0.5V反向偏置下的反向电流密度高达300kA/cm(2)。应变相关电流电压(I-V)测量结果表明，随着单轴拉应力的增加，隧道电流峰值减小，而在1.3 Gpa的压应力作用下，沿生长方向的峰值电流增加了48%，揭示了硅能带结构和隧道势垒的应变依赖关系。通过4.2K下的电导测量，探讨了声子对间接隧穿过程的贡献。测量结果表明，声子峰位于与横向声学声子和横向光学声子相对应的能量处。此外，低温电导测量被扩展到更高的偏置，以识别带隙中的潜在杂质态。结果表明，最有可能的杂质，即来自催化剂颗粒的金，是无法检测到的，这一发现也得到了本文报道的Esaki二极管优异的器件性能的支持。
We report on the fabrication and characterization of silicon nanowire tunnel diodes. The silicon nanowires were grown on p-type Si substrates using Au-catalyzed vapor liquid solid growth and in situ n-type doping. Electrical measurements reveal Esaki diode characteristics with peak current densities of 3.6 kA/cm(2), peak-to-valley current ratios of up to 4.3, and reverse current densities of up to 300 kA/cm(2) at 0.5 V reverse bias. Strain-dependent current voltage (I-V) measurements exhibit a decrease of the peak tunnel current with uniaxial tensile stress and an increase of 48% for 1.3 GPa compressive stress along the < 111 > growth direction, revealing the strain dependence of the Si band structure and thus the tunnel barrier. The contributions of phonons to the indirect tunneling process were probed by conductance measurements at 4.2 K. These measurements show phonon peaks at energies corresponding to the transverse acoustical and transverse optical phonons. In addition, the low-temperature conductance measurements were extended to higher biases to identify potential impurity states in the band gap. The results demonstrate that the most likely impurity, namely, Au from the catalyst particle, is not detectable, a finding that is also supported by the excellent device properties of the Esaki diodes reported here.