Nanometre-scale germanium photodetector enhanced by a near-infrared dipole antenna
Nanometre-scale germanium photodetector enhanced by a near-infrared dipole antenna
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DOI：
10.1038/nphoton.2008.30
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发表时间：
2008-04-01
期刊：
影响因子：
35
通讯作者：
Miller, David A. B.
中科院分区：
文献类型：
--
作者：
Tang, Liang;Kocabas, Sukru Ekin;Miller, David A. B.
光学和电子学融合的一个关键挑战是，光学的微米尺度远大于现代电子器件的纳米尺度。在通过光电探测器从光子到电子的转换中，这种尺寸不兼容性通常会导致功耗、面积、延迟和噪声方面的实质性损失（1 - 4）。通过使用亚波长有源区，光电探测器可以做得更小;然而，由于光的衍射极限，这可能导致非常低的响应度。在这里，我们利用半波赫兹偶极天线（长度类似于380 nm）的想法，从无线电波，但在近红外波长（长度类似于1.3 μ m），集中辐射到纳米级的锗光电探测器。这在亚波长锗元件中产生的光电流中给出了20倍的偏振对比度，该锗元件具有0.00072 μ m（3）的有效体积，该尺寸比先前在这样的波长下证明的检测器小两个数量级。
A critical challenge for the convergence of optics and electronics is that the micrometre scale of optics is significantly larger than the nanometre scale of modern electronic devices. In the conversion from photons to electrons by photodetectors, this size incompatibility often leads to substantial penalties in power dissipation, area, latency and noise(1 - 4). A photodetector can be made smaller by using a subwavelength active region; however, this can result in very low responsivity because of the diffraction limit of the light. Here we exploit the idea of a half-wave Hertz dipole antenna (length similar to 380 nm) from radio waves, but at near-infrared wavelengths (length similar to 1.3 mu m), to concentrate radiation into a nanometre-scale germanium photodetector. This gives a polarization contrast of a factor of 20 in the resulting photocurrent in the subwavelength germanium element, which has an active volume of 0.00072 mu m(3), a size that is two orders of magnitude smaller than previously demonstrated detectors at such wavelengths.