Strain‐Modulated Dominant Response Band of Self‐Powered Photodetector Based on WSe₂ Lateral PN Homojunction

Flexible devices based on 2D materials have shown promising application capacity in next-generation optoelectronics. The lack of inversion centrosymmetry renders odd-layered 2D transition metal dichalcogenides (TMDs) to be piezoelectric, which means the properties modulation of them gets rid of the limit to the gate voltage and they can be directly gated by external strain. Here, a self-powered photodetector based on WSe₂ lateral PN homojunction is constructed, which exhibits excellent current rectification behavior with a rectification ratio of 1.8 × 10³. Further, under the modulation of uniaxial tensile strain, a novel phenomenon that the dominant response waveband can be tuned from 550 to 800 nm by 1.04% tensile strain is observed. The maximum photoresponsivity to 800 nm incident laser reach 216.7 mA W^-1 with 455% improvement has been demonstrated when a 1.04% tensile strain is applied. This work provides an example of multi-band response light detection with strain manipulation on a single photodetector device, which shows significant prospect in adaptable artificial vision application.