Passivation of Indium Selenide: Suppressing Polymer-Induced Doping through Redox Activation

Polymers have played a critical role as passivation and dielectric layers in two-dimensional semiconductor device applications. However, the impact of functional groups in polymers, which can significantly affect channel materials and induce undesirable doping effects, remains largely unexplored. Here, we focused on the influence of functional groups on the channel material and investigated methods to mitigate the abnormal doping effects, thereby enhancing polymer stability. To achieve this, a novel composite passivation layer was introduced to stabilize the partial charges within the polymer. The composite was prepared by simply mixing benzyl viologen (BV) into poly(methyl methacrylate) (PMMA). Utilizing Raman spectroscopy and electrical characterization based on field-effect transistor measurements, we systematically investigated the impacts of polymer on indium selenide (InSe). The results highlight the p-type doping effect induced by PMMA on InSe and demonstrate effective charge neutralization achieved by the PMMA/BV composite. Our findings offer new insights into improving polymer stability and durability in next-generation electronic applications.