Ultrahigh photoresponsivity MoS2 photodetector with tunable photocurrent generation mechanism
Ultrahigh photoresponsivity MoS2 photodetector with tunable photocurrent generation mechanism
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DOI：
10.1088/1361-6528/aae17e
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发表时间：
2018-10
期刊：
影响因子：
3.5
通讯作者：
Guangjian Wu;Xudong Wang;Yan Chen;Zhen Wang;H. Shen;T. Lin;Weida Hu;Jianlu Wang;Shantao Zhang;Xiangjian Meng;J. Chu
中科院分区：
文献类型：
--
作者：
Guangjian Wu;Xudong Wang;Yan Chen;Zhen Wang;H. Shen;T. Lin;Weida Hu;Jianlu Wang;Shantao Zhang;Xiangjian Meng;J. Chu
具有SiO2/Si衬底上的二维（2D）材料的光电探测器已经被广泛探索。然而，由于2D材料的低效率光吸收，这些光电探测器通常遭受大的栅极电压和相对低的光响应性。在这里，我们开发了一种基于Al 2 O3/ITO（氧化铟锡）/SiO2/Si衬底的MoS 2光电探测器，其光响应度为2.7 × 104 A W−1。大部分入射光被堆叠的Al 2 O3/ITO/SiO2衬底的界面反射，这显著增加了2D材料的光吸收。借助更薄且高-κ的Al 2 O3电介质，在栅极电压不超过2 V的情况下，电流开/关比可以超过109。增强的栅极调节还带来了相对较高的迁移率（84 cm 2 V-1 s-1）和亚阈值摆幅（104 mV dec-1）。此外，两种不同的光电流产生机制也被揭示通过调整栅极电压。反射增强衬底辅助的MoS 2光电探测器为提高二维材料光电探测器的性能提供了一种新的思路，可以与其他方法完美结合。
Photodetectors with two-dimensional (2D) materials on a SiO2/Si substrate have been extensively explored. However, these photodetectors often suffer from a large gate voltage and relatively low photoresponsivity due to the low efficiency light absorption of 2D materials. Here, we develop a MoS2 photodetector based on the Al2O3/ITO (indium tin oxide)/SiO2/Si substrate with ultrahigh photoresponsivity of 2.7 × 104 A W−1. Most of the incident light is reflected by the interface of stacked Al2O3/ITO/SiO2 substrate, which significantly increases the light absorption of 2D materials. With the help of thinner and high-κ Al2O3 dielectric, the current ON/OFF ratio could exceed 109 with a gate voltage no more than 2 V. Enhanced gate regulation also brings about a relatively high mobility of 84 cm2 V−1 s−1 and subthreshold swing of 104 mV dec−1. Additionally, two different photocurrent generation mechanisms have also been revealed by tuning the gate voltage. The reflection-enhancement substrate assisted MoS2 photodetector provides a new idea for improving the performance of 2D material photodetectors, which can be perfectly combined with other methods.