Polarization‐Resolved Broadband MoS 2 /Black Phosphorus/MoS 2 Optoelectronic Memory with Ultralong Retention Time and Ultrahigh Switching Ratio

The rapidly emerging requirement for device miniaturization and structural flexibility make 2D semiconductors and their van der Waals (vdWs) heterostructures extremely attractive for nonvolatile optoelectronic memory (NOM) applications. Although several concepts for 2D NOM have been demonstrated, multi‐heterojunction devices capable of further improving storage performance have received little attention. This work reports a concept for MoS 2 /black phosphorus (BP)/MoS 2 multi‐heterojunction NOM with artificial trap sites through the BP oxidation, in which the trapped holes at BP/PO x interface intrigue a persistent photoconductivity that hardly recovers within the experimental time scales (exceeding 10 4 s). As a result of the interfacial trap‐controlled charge injection, the device exhibits excellent photoresponsive memory characteristics, including a record high detectivity of ≈1.2 × 10 16 Jones, a large light‐to‐dark switching ratio of ≈1.5 × 10 7 , an ultralow off‐state current of ≈1.2 pA, and an outstanding multi‐bit storage capacity (11 storage states, 546 nC state –1 ). In addition, the middle BP layer in the multi‐heterojunction enables broadband spectrum distinction (375–1064 nm), together with a high polarization ratio of 8.4. The obtained results represent the significant step toward the high‐density integration of optoelectronic memories with 2D vdWs heterostructures.