High-Performance Flexible 2D Tellurium Semiconductor Grown by Isolated Plasma Soft Deposition for Wearable and Flexible Temperature Sensors

High-quality flexible 2D tellurium (Te) semiconductors on a six-inch Si wafer and polyethylene terephthalate substrate using the isolated plasma soft deposition (IPSD) technique are successfully fabricated. Unlike conventional sputtering systems, the IPSD process minimizes direct plasma irradiation and plasma damage, thereby preserving the unique helical chain structure of the 2D Te layer. The integration of oxygen plasma treatment and in situ substrate heating significantly enhanced both the adhesion and crystallinity of the 2D Te layer. The optimized 2D Te layer exhibited exceptional properties, including a high carrier mobility of 103 cm² V⁻¹ s⁻¹, a smooth surface roughness of 0.778 nm, and a critical bending radius of 12 mm. When integrated into temperature sensors, the 2D Te/PET demonstrated high sensitivity, exhibiting a negative temperature coefficient response across the 20–40 °C range. Moreover, the IPSD-grown 2D Te layer demonstrated outstanding mechanical flexibility, with minimal resistance changes (<4%) during both bending and rolling tests. Long-term stability assessments conducted over 100 days revealed resistance variations of less than 1%, highlighting the material's robust reliability. These findings position the IPSD process as a promising physical vapor deposition technique for scalable fabrication of large-area 2D Te layers, enabling their integration into wearable and flexible electronic devices.