All‐Layered 2D Optoelectronics: A High‐Performance UV–vis–NIR Broadband SnSe Photodetector with Bi₂Te₃ Topological Insulator Electrodes

Abstract

Nanoelectronics is in urgent demand of exceptional device architecture with ultrathin thickness below 10 nm and dangling‐bond‐free surface to break through current physical bottleneck and achieve new record of integration level. The advance in 2D van der Waals materials endows scientists with new accessibility. This study reports an all‐layered 2D Bi2Te3‐SnSe‐Bi2Te3 photodetector, and the broadband photoresponse of the device from ultraviolet (370 nm) to near‐infrared (808 nm) is demonstrated. In addition, the optimized responsivity reaches 5.5 A W−1, with the corresponding eternal quantum efficiency of 1833% and detectivity of 6 × 1010 cm Hz1/2 W−1. These figures‐of‐merits are among the best values of the reported all‐layered 2D photodetectors, which are several orders of magnitude higher than those of the previous SnSe photodetectors. The superior device performance is attributed to the synergy of highly conductive surface state of Bi2Te3 topological insulator, perfect band alignment between Bi2Te3 and SnSe as well as small interface potential fluctuation. Meanwhile, the all‐layered 2D device is further constructed onto flexible mica substrate and its photoresponse is maintained roughly unchanged upon 60 bending cycles. The findings represent a fundamental scenario for advancement of the next generation high performance and high integration level flexible optoelectronics.

Two‐dimensional heterostructure promoted infrared photodetection devices

“…Designing new architectures or exploring new fabrication techniques to realize more precise and improved IR photodetection, have attracted many scientists . Son et al discovered a fabrication method to build integrated 3D electronic and optoelectronic 2DHs with graphene stops that consisted of graphene/fluorographene heterostructures (shown in Figure E).…”

WSe2 Photovoltaic Device Based on Intramolecular p–n Junction

“…A high‐performance WSe 2 phototransistor with degenerately p‐doped WSe 2 as 2D contact has also been reported . In addition, flexible photoresistors have been realized based on SnSe and SnS, showing great potentials of 2DLMs in wearable devices. For the photovoltaic devices, junctions are essential to provide depletion regions in which the photoinduced electron–hole pairs can be separated rapidly.…”

High Responsivity and Photovoltaic Effect Based on Vertical Transport in Multilayer α‐In2Se3

“…2D layered materials, with their ever‐increasing assortment, have attracted significant interest toward high performance and novel optoelectronic devices, including those for flexible and/or transparent technologies . The presence of a finite bandgap in these 2D semiconductors (except monolayer graphene) makes them promising for visible and infrared (IR) photodetectors with excellent spectral response and gain while the flexibility of transferring them on any substrate without being plagued by lattice mismatches provides an excellent platform for heterogeneous and extreme bandgap engineering.…”

“…2D layered materials, with their ever-increasing assortment, have attracted significant interest toward high performance and novel optoelectronic devices, including those for flexible and/or transparent technologies. [1,2] The presence of a finite bandgap in these 2D semiconductors (except monolayer graphene) makes them promising for visible and infrared (IR) photodetectors with excellent spectral response and gain while the flexibility of transferring them on any substrate without being plagued by lattice mismatches provides an excellent platform for heterogeneous and extreme bandgap engineering. Graphene, transition metal dichalcogenides (TMDs), and black phosphorous and their heterostructures exhibit intriguing material behaviors, which are strongly dependent on the number of layers (or thickness) and have attracted the attention of the device community toward multifunctional optical devices.…”