Ultraweak light detectors have wide-ranging important applications such as astronomical observation, remote sensing, laser ranging, and night vision. Current commercial ultraweak light detectors are commonly based on a photomultiplier tube or an avalanche photodiode, and they are incompatible with microelectronic devices for digital imaging applications, because of their high operating voltage and bulky size. Herein, we develop a memory phototransistor for ultraweak light detection, by exploiting the charge-storage accumulative effect in CdS nanoribbon. The memory phototransistors break the power law of traditional photodetectors and follow a time-dependent exponential-association photoelectric conversion law. Significantly, the memory phototransistors exhibit ultrahigh responsivity of 3.8 × 10⁹ A W⁻¹ and detectivity of 7.7 × 10²² Jones. As a result, the memory phototransistors are able to detect ultraweak light of 6 nW cm⁻² with an extremely high sensitivity of 4 × 10⁷. The proposed memory phototransistors offer a design concept for ultraweak light sensing devices.

超弱光检测器具有广泛的重要应用，例如天文观测，遥感，激光测距和夜视。当前的商用超弱光检测器通常基于光电倍增管或雪崩光电二极管，并且由于其高工作电压和体积大而与用于数字成像应用的微电子设备不兼容。在本文中，我们通过利用CdS纳米带中的电荷累积效应，开发了一种用于超弱光检测的存储光电晶体管。存储器光电晶体管打破了传统光电探测器的功率定律，并遵循与时间有关的指数关联光电转换定律。显着的是，存储光电晶体管表现出3.8×10 ⁹  A W的超高响应度^-1，探测灵敏度为7.7×10 ²² Jones。结果，存储光电晶体管能够以4×10 ⁷的极高灵敏度检测6nW cm ^-2的超弱光。所提出的存储器光电晶体管为超弱光感测设备提供了一种设计理念。