Self-driven, broadband and ultrafast photovoltaic detectors based on topological crystalline insulator SnTe/Si heterostructures

Abstract

As a new class of materials that have been proved to possess exotic surface state properties protected by mirror symmetry, topological crystalline insulators (TCIs) have attracted much attention owing to their promising applications in dissipationless novel electronic and optoelectronic devices. Herein, we demonstrated the fabrication of high-quality TCI SnTe/Si heterostructures with excellent diode characteristics by a simple chemical vapor deposition (CVD) process. The SnTe/Si heterostructures exhibited pronounced photovoltaic behavior under light illumination, enabling the function of the devices as self-driven, stable and broadband photovoltaic detectors with a detection range from 254 nm ultraviolet (UV) light to 1550 nm near-infrared (NIR) light. Further investigation of the device characteristics revealed an ultrafast response speed of ∼8 μs and a high detectivity of 8.4 × 10¹² Jones (Jones = cm Hz^1/2 W⁻¹) for the heterostructures, because the separation and transport of photogenerated carriers were greatly facilitated due to the existence of built-in potential at the SnTe/Si interface. To the best of our knowledge, this is the first time the TCI/Si heterostructure is utilized in photovoltaic and photodetecting devices. Given the excellent performance of the SnTe/Si heterostructures, they may have important applications in next-generation optoelectronic devices fabricated from topological insulator materials.