Phototransistors are light-sensitive devices featuring a high dynamic range, low-light detection, and mechanisms to adapt to different ambient light conditions. These features are of interest for bioinspired applications such as artificial and restored vision. In this work, we report on a graphene-based phototransistor exploiting the photogating effect that features picowatt- to microwatt-level photodetection, a dynamic range covering six orders of magnitude from 7 to 10⁷ lux, and a responsivity of up to 4.7 × 10³ A/W. The proposed device offers the highest dynamic range and lowest optical power detected compared to the state of the art in interfacial photogating and further operates air stably. These results have been achieved by a combination of multiple developments. For example, by optimizing the geometry of our devices with respect to the graphene channel aspect ratio and by introducing a semitransparent top-gate electrode, we report a factor 20–30 improvement in responsivity over unoptimized reference devices. Furthermore, we use a built-in dynamic range compression based on a partial logarithmic optical power dependence in combination with control of responsivity. These features enable adaptation to changing lighting conditions and support high dynamic range operation, similar to what is known in human visual perception. The enhanced performance of our devices therefore holds potential for bioinspired applications, such as retinal implants.

中文翻译：

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用于高动态范围应用的工程石墨烯光电晶体管

光电晶体管是光敏器件，具有高动态范围、低光检测和适应不同环境光条件的机制。这些功能对于仿生应用（例如人工视力和恢复视力）很有意义。在这项工作中，我们报告了一种基于石墨烯的光电晶体管，它利用光电门控效应，具有皮瓦到微瓦级的光电检测功能，动态范围涵盖从7到10 ⁷勒克斯的六个数量级，响应度高达4.7 × 10 ³秋冬。与界面光选通领域的现有技术相比，所提出的设备提供了最高的动态范围和最低的光功率，并且进一步稳定地运行空气。这些成果是通过多种开发的结合取得的。例如，通过根据石墨烯通道纵横比优化我们器件的几何形状，并引入半透明顶栅电极，我们报告称响应度比未优化的参考器件提高了 20-30 倍。此外，我们使用基于部分对数光功率依赖性的内置动态范围压缩以及响应率控制。这些功能能够适应不断变化的照明条件并支持高动态范围操作，类似于人类视觉感知。因此，我们设备的增强性能具有仿生应用的潜力，例如视网膜植入物。