This work reports a nanostructure resonant tunnelling diode-photodetector (RTD-PD) device and demonstrates its operation as a controllable, optically-triggered excitable spike generator. The top contact layer of the device is designed with a nanopillar structure 500 nm in diameter) to restrain the injection current, yielding therefore lower energy operation for spike generation. We demonstrate experimentally the deterministic optical triggering of controllable and repeatable neuron-like spike patterns in the nanostructure RTD-PDs. Moreover, we show the device's ability to deliver spiking responses when biased in both regions adjacent to the negative differential conductance (NDC) region, the so-called 'peak' and 'valley' points of the current-voltage ($I$-$V$) characteristic. This work also demonstrates experimentally key neuron-like dynamical features in the nanostructure RTD-PD, such as a well-defined threshold (in input optical intensity) for spike firing, as well as the presence of spike firing refractory time. The optoelectronic and chip-scale character of the proposed system together with the deterministic, repeatable and well controllable nature of the optically-elicited spiking responses render this nanostructure RTD-PD element as a highly promising solution for high-speed, energy-efficient optoelectronic artificial spiking neurons for novel light-enabled neuromorphic computing hardware.

翻译：本工作报告了一种纳米结构共振隧穿二极管-光电探测器（RTD-PD）器件，并演示了其作为可控、光学触发的可激发尖峰发生器的工作机制。器件的顶层接触层设计有直径为500纳米的纳米柱结构以限制注入电流，从而在尖峰生成中实现更低的能量消耗。我们通过实验证明了纳米结构RTD-PD中可控且可重复的类神经元尖峰模式的光学确定性触发。此外，我们展示了该器件在偏置于负微分电导（NDC）区域两侧（即电流-电压（$I$-$V$）特性曲线的所谓“峰值”和“谷值”点）时产生尖峰响应的能力。本工作还通过实验证明了纳米结构RTD-PD中关键的类神经元动态特征，例如尖峰发射具有明确的阈值（输入光强）以及尖峰发射后的不应期。该系统的光电特性和芯片级尺度，加上光学诱发尖峰响应的确定性、可重复性和良好可控性，使得这种纳米结构RTD-PD元件成为高速、节能的光电人工尖峰神经元的极具前景的解决方案，可用于新型光启神经形态计算硬件。