WSe₂ Interdigitated p-n Homojunction for Broadband High-Performance Imaging Detection through Localization Effect Synergizes

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 WSe₂ 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 WSe₂, which effectively promotes charge separation across the broadband. The device exhibits remarkable detectivity values of 4.58×10⁹ Jones (365 nm), 3.57×10¹⁰ Jones (470 nm), 1.29×10¹¹ Jones (550 nm), 1.13×10¹² Jones (850 nm), and 1.52×10¹² (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.