Size, composition, and doping effects on In(Ga)As nanowire/Si tunnel diodes probed by conductive atomic force microscopy
Size, composition, and doping effects on In(Ga)As nanowire/Si tunnel diodes probed by conductive atomic force microscopy
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DOI：
10.1063/1.4768001
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发表时间：
2012-12
影响因子：
4
通讯作者：
Tao Yang;S. Hertenberger;S. Morkötter;G. Abstreiter;G. Koblmüller
中科院分区：
文献类型：
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作者：
Tao Yang;S. Hertenberger;S. Morkötter;G. Abstreiter;G. Koblmüller
利用导电原子力显微镜研究了不同参数对分子束外延生长的本征n型In（Ga）As纳米线的室温带间隧穿特性的影响。通过将p型衬底掺杂水平增加到>1 × 1019 cm−3，可以获得大的带间隧道电流（>40 kA/cm 2）和降低的击穿电压。正向偏置下的电流映射揭示了NW/Si异质结隧道二极管的双峰分布，其表现出负微分电阻（NDR，江崎二极管）或高过剩电流（没有NDR）。通过将NW直径从1090 nm缩小到1025 nm，NDR型二极管中的峰谷电流比增加，并在最大值为103时饱和。增加富In三元InGaAs纳米线中的Ga含量（xGa高达0.1）可以保留NDR行为，而峰值电流则由于InGaAs中费米能的降低而向较低电压移动。谱带轮廓计算进行了进一步的.
We investigate the effect of various parameters on the room–temperature interband tunneling characteristics of molecular beam epitaxy grown, intrinsically n-type In(Ga)As nanowires (NWs) on p-type silicon (Si) substrate using conductive atomic force microscopy. Large interband tunnel currents (>40 kA/cm2) and reduced breakdown voltages are obtained by increasing the p-type substrate doping level to >1 × 1019 cm−3. Current mapping under forward bias reveals a bimodal distribution of NW/Si hetero-junction tunnel diodes exhibiting either negative differential resistance (NDR, Esaki diode) or high excess currents (without NDR). By downscaling the NW diameter from ∼90 nm to ∼25 nm, peak-to-valley current ratios in NDR-type diodes increase and saturate with maximum values of ∼3. Increasing Ga content (xGa up to ∼0.1) in In–rich ternary InGaAs NWs preserves the NDR behavior, while the peak current shifts to lower voltages due to reduced Fermi energy in InGaAs. Band profile calculations were performed to further ...