Position-dependent and millimetre-range photodetection in phototransistors with micrometre-scale graphene on SiC
Position-dependent and millimetre-range photodetection in phototransistors with micrometre-scale graphene on SiC
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DOI：
10.1038/nnano.2017.46
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发表时间：
2017-07-01
影响因子：
38.3
通讯作者：
Chen, Yong P.
中科院分区：
文献类型：
--
作者：
Sarker, Biddut K.;Cazalas, Edward;Chen, Yong P.
石墨烯非凡的光学和电子特性使其成为高性能光电探测器的一个有前途的组件。然而，在迄今为止展示的典型石墨烯基光电探测器中，光响应仅来自石墨烯附近的特定位置，其面积远小于器件尺寸。对于许多光电器件应用，期望在大得多的区域上获得光响应和位置灵敏度。在这里，我们报告的空间依赖性的背栅石墨烯场效应晶体管（GFET）的碳化硅（SiC）衬底上的光响应扫描聚焦激光束在GFET。GFET显示出非局部光响应，即使当SiC衬底被照射在距离大于500 μ m的石墨烯。光响应度和光电流可以根据照射位置而变化超过一个数量级。我们的观察结果解释了一个数值模型的基础上，在基板中的光激发载流子的电荷输运。
The extraordinary optical and electronic properties of graphene make it a promising component of high-performance photodetectors. However, in typical graphene-based photodetectors demonstrated to date, the photoresponse only comes from specific locations near graphene over an area much smaller than the device size. For many optoelectronic device applications, it is desirable to obtain the photoresponse and positional sensitivity over a much larger area. Here, we report the spatial dependence of the photoresponse in backgated graphene field-effect transistors (GFET) on silicon carbide (SiC) substrates by scanning a focused laser beam across the GFET. The GFET shows a nonlocal photoresponse even when the SiC substrate is illuminated at distances greater than 500 mu m from the graphene. The photoresponsivity and photocurrent can be varied by more than one order of magnitude depending on the illumination position. Our observations are explained with a numerical model based on charge transport of photoexcited carriers in the substrate.