Vertical Barrier Heterostructures for Reliable, Robust, and High-Performance Ultraviolet Detection.

Photodetectors based on low-dimensional materials usually suffer from serious optical power-dependent photoresponse and low reliability, particularly in the ultraviolet regime. The barrier photodetector is an effective and reliable strategy where the barrier layer can block the low-energy charge carriers while allowing for a flow of the high-energy photocarriers. Here, vertical barrier heterostructure photodetectors (VBHPs), consisting of a graphene bottom electrode, a MoS light absorber, and an h-BN energy barrier, for reliable, robust, and high-performance ultraviolet detection are reported. The asymmetric barrier distribution in the conduction/valence band at the MoS /h-BN interface results in an ultralow noise current of 1.69 × 10 A Hz at room temperature, stable photo on/off states exceeding 10 cycles at 300 K and 400 K, a light power-independent high responsivity of 416.2 mA W at 360 nm, a high photo on-off ratio of 1.2 × 10 at 360 nm, high measured detectivities (3.2 × 10 Jones at 266 nm and 9.9 × 10 Jones at 360 nm), and wide linear dynamic ranges. The VBHPs show a high potential for new-type reliable ultraviolet detection.