WSe ₂ Interdigitated p‐n Homojunction for Broadband High‐Performance Imaging Detection through Localization Effect Synergizes

ABSTRACT Due to the inherent bandgap limitations of traditional semiconductors, achieving a broadband response typically requires complex heterostructures, which suffer from lattice mismatch and compromised performance. Herein, we propose a novel oxygen plasma treatment WSe 2 homojunction strategy to overcome this trade‐off. A simple mask‐assisted magnetron sputtering technique was employed to fabricate an interdigital p‐n homojunction photodetector. The key innovation lies in creating a staggered type‐II band alignment via localized oxygen doping on pure WSe 2 , which effectively promotes charge separation across the broadband. The device exhibits remarkable detectivity values of 4.58×10 9 Jones (365 nm), 3.57×10 10 Jones (470 nm), 1.29×10 11 Jones (550 nm), 1.13×10 12 Jones (850 nm), and 1.52×10 12 (1064 nm) at a bias of 0 V. Clear “HIT” pixel images with distinct edges were obtained at all these wavelengths. At 1064 nm, the device achieved a high on/off ratio of 2,208 and fast rise/fall times of 59 µs and 18 µs, respectively. Through wide‐spectrum imaging and high‐frequency response testing, the device demonstrates excellent potential for next‐generation, high‐performance broadband imaging systems.