Tri‐HfGeTe 4 : Hybrid Tri/Tetragonal 2D Layers with Strong Anisotropy for Self‐Powered In‐Sensor Multidimensional Computing

Multidimensional optical sensing is crucial for advanced visual systems to accurately identify targets in complex environments. Most current two‐dimensional (2D) computational devices, however, only respond to light intensity. A key challenge is to develop novel 2D materials capable of simultaneous polarization‐resolved and spectrum‐selective detection under low‐power operation. Herein, we demonstrate that tri‐HfGeTe 4 , a narrow‐bandgap (0.6 eV) 2D semiconductor, enables zero‐bias, spectrally selective, polarity‐sensitive photodetection for self‐powered in‐sensor multidimensional computing. Especially, 2D tri‐HfGeTe 4 features a novel low‐symmetry puckered layered structure, uniquely composed of trigonal and tetragonal rings, with the trigonal motifs being reported for the first time in 2D materials. Significantly, such a unique structure gives rise to significant in‐plane anisotropy, with ratios reaching 2.08 at 671 nm and 1.86 at 1064 nm. Notably, the dominant polarization orientations of visible light and near‐infrared light are orthogonal to each other, which greatly facilitates dual‐band information discrimination. In addition, driven by the photothermoelectric effect, 2D tri‐HfGeTe 4 devices can efficiently modulate bipolar photocurrent for feature extraction without external power. More importantly, the 2D tri‐HfGeTe 4 system achieves more accurate target recognition with a high Intersection over Union (IoU) of 91%. This work paves the way for compact, efficient multidimensional visual perception systems, supporting the development of robust in‐sensor computing.