Noise and detectivity limits in organic shortwave infrared photodiodes with low disorder
Noise and detectivity limits in organic shortwave infrared photodiodes with low disorder
复制标题
低无序有机短波红外光电二极管的噪声和探测率限制
DOI：
10.1038/s41528-020-0069-x
复制
发表时间：
2020
影响因子：
14.6
通讯作者：
Ng, Tse Nga
中科院分区：
文献类型：
--
作者：
Wu, Zhenghui;Li, Ning;Eedugurala, Naresh;Azoulay, Jason D.;Leem, Dong-Seok;Ng, Tse Nga
为了实现红外探测器的高探测率，降低器件噪声是关键。然而，对于非晶体半导体，缺少一个基本的框架来理解和预测无序对暗电流的影响。本文介绍了典型有机体异质结光电二极管中噪声电流的实验和建模研究，该二极管具有10种施主-受主组合，波长在800至1600 nm之间。与使用富勒烯衍生物的器件相比，在使用非富勒烯受体（nfa）的器件中发现了显著降低的噪声和更高的探测性。变温态密度测量结果表明，NFA共混物的低噪声归因于带尾态分布的急剧下降。考虑到无序性，我们建立了一个通用的物理模型来解释热噪声对有效带隙和带尾扩展的依赖。该模型为固有无序红外光电二极管在不同探测波长下可获得的最大探测率提供了理论目标。
To achieve high detectivity in infrared detectors, it is critical to reduce the device noise. However, for non-crystalline semiconductors, an essential framework is missing to understand and predict the effects of disorder on the dark current. This report presents experimental and modeling studies on the noise current in exemplar organic bulk heterojunction photodiodes, with 10 donor–acceptor combinations spanning wavelength between 800 and 1600 nm. A significant reduction of the noise and higher detectivity were found in devices using non-fullerene acceptors (NFAs) in comparison to those using fullerene derivatives. The low noise in NFA blends was attributed to a sharp drop off in the distribution of bandtail states, as revealed by variable-temperature density-of-states measurements. Taking disorder into account, we developed a general physical model to explain the dependence of thermal noise on the effective bandgap and bandtail spread. The model provides theoretical targets for the maximum detectivity that can be obtained at different detection wavelengths in inherently disordered infrared photodiodes.