Biodegradable albumen dielectrics for high-mobility MoS₂ phototransistors

This work demonstrates the fabrication and characterization of single-layer MoS₂ field-effect transistors using biodegradable albumen (chicken eggwhite) as gate dielectric. By introducing albumen as an insulator for MoS₂ transistors high carrier mobilities (up to ~90 cm² V^-1 s^-1) are observed, which is remarkably superior to that obtained with commonly used SiO₂ dielectric which we attribute to ionic gating due to the formation of an electric double layer in the albumen MoS₂ interface. In addition, the investigated devices are characterized upon illumination, observing responsivities of 4.5 AW^-1 (operated in photogating regime) and rise times as low as 52 ms (operated in photoconductivity regime). The presented study reveals the combination of albumen with van der Waals materials for prospective biodegradable and biocompatible optoelectronic device applications. Furthermore, the demonstrated universal fabrication process can be easily adopted to fabricate albumen-based devices with any other van der Waals material.