Tunable Drift–Diffusion Synergy in Suspended Te Nanowires for Multistate Photodetection
Ni Sheng, Cheng-Tang Pan, Xin Li, Fengyi Zhu, Shuangli Mi, Xuhao Fan, Rui Zhang, Xutao Zhang, Haibiao Guan, He Zhu, Jingzhou Li, Weiwei Tang, Haibo Shu, Changlong Liu, Guanhai Li, Xiaoshuang Chen
Abstract
Tuning the interplay between photoconductive (drift-driven) transport and photothermoelectric (diffusion-driven) transport in a single device remains crucial for next-generation optoelectronics and in-sensor computing. Here, we present a suspended tellurium nanowire (Te NW) photodetector that concurrently harnesses and actively balances these two transports using asymmetric (local) or symmetric (flood) illumination in tandem with a bias voltage. This enables on-demand transitions from diffusion-dominated to drift-dominated photoresponses at room temperature, a feat not realized in prior Te-based detectors. Under zero bias with local illumination, robust photothermoelectric diffusion yields positive or negative photocurrents, with a responsivity R i of 124.28 A/W and specific detectivity ( D *) of 7.80 × 10 11 Jones. Conversely, flood illumination under finite bias triggers photoconductive drift, with a peak responsivity R i of 65.03–68.79 A/W and D * of 7.99 × 10 10 –8.47 × 10 10 Jones. By programming the illumination and bias conditions, we realize positive, negative, or zero photocurrent states, forming a three-mode response platform. Remarkably, the device exhibits a sub-100 μs response time and retains stable detection under ambient conditions, illustrating its viability for real-world applications. This work establishes a versatile blueprint for broadband, multistate photodetection toward in-sensor computing tasks.