Diameter-Dependent Internal Gain in Ohmic Ge Nanowire Photodetectors
Diameter-Dependent Internal Gain in Ohmic Ge Nanowire Photodetectors
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DOI：
10.1021/nl100136b
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发表时间：
2010-06-01
期刊：
影响因子：
10.8
通讯作者：
Jo, Moon-Ho
中科院分区：
文献类型：
--
作者：
Kim, Cheol-Joo;Lee, Hyun-Seung;Jo, Moon-Ho
本文报道了本征锗纳米线（NW）光电探测器的光电导增益随直径的变化。利用扫描光电流成像技术，我们证明了光生载流子输运是由空穴沿沿着Ge纳米线的漂移决定的，从而保证了薄纳米线的内部增益高达10（3）。结果发现，增益和光电导的大小都成反比的NW直径范围从50到300 nm。我们将我们的观察结果归因于不同直径的Ge纳米线上的有效空穴载流子密度的变化，作为场效应的结果，从直径相关的人口的表面捕获的电子，沿着与模型计算。我们的观察代表了半导体纳米线内部增益的固有尺寸效应，从而为纳米光电子学提供了新的见解。
We report a diameter-dependent photoconduction gain in intrinsic Ge nanowire (NW) photodetectors. By employing a scanning photocurrent imaging technique, we provide evidence that the photocarrier transport is governed by the hole drift along the Ge NWs, ensuing the higher internal gain up to similar to 10(3) from the thin NWs. It is found that the magnitudes of both gain and photoconductivity are inversely proportional to the NW diameter ranging from 50 to 300 nm. We attribute our observations to the variation in the effective hole carrier density upon varying diameters of Ge NWs, as a result of field effects from the diameter-dependent population of the surface-trapped electrons, along with a model calculation. Our observations represent inherent size effects of internal gain in semiconductor NWs, thereby provide a new insight into nano-optoelectronics.