Effect of the nanowire diameter on the linearity of the response of GaN-based heterostructured nanowire photodetectors
Effect of the nanowire diameter on the linearity of the response of GaN-based heterostructured nanowire photodetectors
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DOI：
10.1088/1361-6528/aab838
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发表时间：
2018-06-22
期刊：
影响因子：
3.5
通讯作者：
Monroy, Eva
中科院分区：
文献类型：
--
作者：
Spies, Maria;Polaczynski, Jakub;Monroy, Eva
纳米线光电探测器的研究，因为它们与灵活的电子产品的兼容性，或用于实现芯片上的光学互连。这种器件的特点是光电流增益很小，但其光响应与光功率呈次线性关系。在这里，我们提出了一个单纳米线光电探测器显示线性响应紫外线照明的研究。它们的结构由结合AlN/GaN/AlN异质结构的GaN纳米线组成，该异质结构产生内部电场。的异质结构的活动被证实的整流行为的电流-电压特性在黑暗中，以及由光响应的幅度和线性的不对称性。在反向偏置（GaN帽部分上的负偏置）下，当纳米线直径低于一定阈值（约80 nm）时，检测器与撞击光功率线性地表现，这对应于由于侧壁处的费米能级钉扎而导致的纳米线茎的总耗尽。在只有部分耗尽的纳米线的情况下，它们的非线性是由它们的中心导电通道的直径在照明下的非线性变化来解释的。
Nanowire photodetectors are investigated because of their compatibility with flexible electronics, or for the implementation of on-chip optical interconnects. Such devices are characterized by ultrahigh photocurrent gain, but their photoresponse scales sublinearly with the optical power. Here, we present a study of single-nanowire photodetectors displaying a linear response to ultraviolet illumination. Their structure consists of a GaN nanowire incorporating an AlN/GaN/AlN heterostructure, which generates an internal electric field. The activity of the heterostructure is confirmed by the rectifying behavior of the current-voltage characteristics in the dark, as well as by the asymmetry of the photoresponse in magnitude and linearity. Under reverse bias (negative bias on the GaN cap segment), the detectors behave linearly with the impinging optical power when the nanowire diameter is below a certain threshold (approximate to 80 nm), which corresponds to the total depletion of the nanowire stem due to the Fermi level pinning at the sidewalls. In the case of nanowires that are only partially depleted, their nonlinearity is explained by a nonlinear variation of the diameter of their central conducting channel under illumination.