Abstract

This article investigates ambipolar organic field-effect transistors, which can exhibit a spatially localized photoelectric effect. This effect consists in the fact that a transistor channel has a narrow photosensitive region in which incident radiation is converted into a photocurrent. The spatial position of which can be controlled by changing the gate voltage \(V_{G}\). Due to this, the dependence of the photocurrent on \(V_{G}\) can reproduce the spatial distribution of the incident radiation intensity. In this work, the response time of phototransistors is studied by numerical modeling. In particular, it is shown that the response time to turning light on in a stepwise manner is a few nanoseconds, while the response time to \(V_{G}\) voltage switching is a few microseconds. The article also studies how changes in various parameters of a phototransistor affect its efficiency. It is shown that the simultaneous improvement of external quantum efficiency (EQE), the photocurrent-to-dark-current-ratio (\(J_{\textrm{ph}}/J_{\textrm{dark}}\)), the spatial resolution, and the response time can be achieved by reducing the channel length. It is also shown that the use of active layer materials in which photogenerated electron–hole pairs are larger than 1 nm can provide higher EQE values and \(J_{\textrm{ph}}/J_{\textrm{dark}}\) without any significant reduction in spatial and temporal resolution.

中文翻译：

---

双极有机场效应晶体管中的时空分辨光电检测。

摘要

本文研究了可以显示空间局部光电效应的双极性有机场效应晶体管。该效果在于以下事实：晶体管沟道具有狭窄的光敏区域，在该光敏区域中，入射辐射被转换为光电流。可以通过改变栅极电压\（V_ {G} \）来控制其空间位置。因此，光电流对\（V_ {G} \）的依赖性可以重现入射辐射强度的空间分布。在这项工作中，通过数值建模研究了光电晶体管的响应时间。特别地，示出了对逐步打开灯的响应时间为几纳秒，而对\（V_ {G} \）的响应时间电压切换是几微秒。本文还研究了光电晶体管各种参数的变化如何影响其效率。结果表明，同时提高了外部量子效率（EQE），光电流与暗电流之比（\（J _ {\ textrm {ph}} / J _ {\ textrm {dark}} \）），空间分辨率和响应时间可以通过减小通道长度来实现。研究还表明，使用光生电子-空穴对大于1 nm的有源层材料可以提供更高的EQE值和\（J _ {\ textrm {ph}} / J _ {\ textrm {dark}} \）而不会在空间和时间分辨率上有任何显着降低。