Photonic crystallization of two-dimensional MoS2 for stretchable photodetectors

Abstract

Low temperature synthesis of high quality two-dimensional (2D) materials directly on flexible substrates remains a fundamental limitation towards scalable realization of robust flexible electronics possessing the unique physical properties of atomically thin structures. Herein, we describe room temperature sputtering of uniform, stoichiometric amorphous MoS₂ and subsequent large area (>6.25 cm²) photonic crystallization of 5 nm 2H-MoS₂ films in air to enable direct, scalable fabrication of ultrathin 2D photodetectors on stretchable polydimethylsiloxane (PDMS) substrates. The lateral photodetector devices demonstrate an average responsivity of 2.52 μW A⁻¹ and a minimum response time of 120 ms under 515.6 nm illumination. Additionally, the surface wrinkled, or buckled, PDMS substrate with conformal MoS₂ retained the photoconductive behavior at tensile strains as high as 5.72% and over 1000 stretching cycles. The results indicate that the photonic crystallization method provides a significant advancement in incorporating high quality semiconducting 2D materials applied directly on polymer substrates for wearable and flexible electronic systems.