Black phosphorus nanodevices at terahertz frequencies: photodetectors and future challenges

TL;DR

This paper reviews recent advances in black phosphorus-based terahertz detectors, highlighting their physical mechanisms, potential applications, and the challenges in developing stable, reliable optoelectronic devices using this material.

Contribution

It provides a comprehensive overview of black phosphorus terahertz detectors, emphasizing physical mechanisms and future challenges for device stability and reliability.

Findings

Black phosphorus detectors operate from 0.26 THz to 3.4 THz.

BP's anisotropic properties enable tailored photoresponse mechanisms.

Future challenges include device stability and integration.

Abstract

The discovery of graphene triggered a rapid rise of unexplored two-dimensional materials and heterostructures having optoelectronic and photonics properties that can be tailored on the nanoscale. Among these materials, black phosphorus (BP) has attracted a remarkable interest thanks to many favorable properties, such as high carrier mobility, in-plane anisotropy, the possibility to alter its transport via electrical gating and direct band-gap, that can be tuned by thickness from 0.3 eV (bulk crystalline) to 1.7 eV (single atomic layer). When integrated in a microscopic field effect transistor (FET), a few-layer BP flake can detect Terahertz (THz) frequency radiation. Remarkably, the in-plane crystalline anisotropy can be exploited to tailor the mechanisms that dominate the photoresponse; a BP-based field effect transistor can be engineered to act as a plasma-wave rectifier, a thermoelectric sensor or a thermal bolometer. Here we present a review on recent research on BP detectors operating from 0.26 THz to 3.4 THz with particular emphasis on the underlying physical mechanisms and the future challenges that are yet to be addressed for making BP the active core of stable and reliable optical and electronic technologies.