Li Xin, Chen Jin, Yu Feilong, Chen Xiaoshuang, Lu Wei, Li Guanhai
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu-Tian Road, Shanghai, 200083, China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
Nano Lett. 2024 Oct 23;24(42):13255-13262. doi: 10.1021/acs.nanolett.4c03450. Epub 2024 Sep 25.
We engineered a two-dimensional Pt/WSe/Ni avalanche photodetector (APD) optimized for ultraweak signal detection at room temperature. By fine-tuning the work functions, we achieved an ultralow dark current of 10 A under small bias, with a noise equivalent power (NEP) of 8.09 fW/Hz. This performance is driven by effective dark barrier blocking and a record-long electron mean free path (123 nm) in intrinsic WSe, minimizing dark carrier replenishment and suppressing noise under an ultralow electric field. Our APD exhibits a high gain of 5 × 10 at a modulation frequency of 20 kHz, effectively balancing gain and bandwidth, a common challenge in traditional photovoltaic-based APDs. By addressing the typical challenges of high noise and low gain and minimizing dependence on high electric fields, this work highlights the potential of 2D materials in developing efficient, low-power, and ultrasensitive photodetections.
我们设计了一种二维Pt/WSe/Ni雪崩光电探测器（APD），该探测器针对室温下的超微弱信号检测进行了优化。通过微调功函数，我们在小偏压下实现了10 A的超低暗电流，噪声等效功率（NEP）为8.09 fW/Hz。这种性能得益于有效的暗势垒阻挡以及本征WSe中创纪录的长电子平均自由程（123 nm），从而在超低电场下将暗载流子补充降至最低并抑制噪声。我们的APD在20 kHz的调制频率下表现出5×10的高增益，有效平衡了增益和带宽，这是传统基于光伏的APD中常见的挑战。通过解决高噪声和低增益的典型挑战并最小化对高电场的依赖，这项工作突出了二维材料在开发高效、低功耗和超灵敏光电探测器方面的潜力。
