Electrically tunable two-dimensional quantum materials for terahertz optoelectronics

Two-dimensional (2D) quantum materials host electronic and collective excitations whose characteristic energies naturally fall within the terahertz (THz) range. Their reduced dimensionality, strong light–matter interaction, and sensitivity to external fields provide opportunities for electrically reconfigurable THz optoelectronics that are difficult to realize using conventional semiconductors and passive optical materials. In this review, we examine how electrical control of carrier density, dielectric screening, ferroelectric polarization, and correlated electronic states can program the THz response of diverse 2D quantum materials, including topological semimetals, semiconductors with strong excitonic effects, ferroelectrics, as well as their moiré superlattices. We first outline the fundamental THz optoelectronic processes, including generation, detection, and modulation, together with the main limitations of conventional materials and device platforms. We then discuss the distinctive properties of major 2D quantum-material platforms that govern their THz response. Recent progress is subsequently reviewed according to the main electrical tuning mechanisms, including electrostatic doping, displacement-field control, and ferroelectric polarization switching. We introduce how these approaches modify THz properties of 2D quantum materials and how the resulting tunability is used in THz optoelectronics with competitive performance and superior electrical tunability. We conclude by discussing the key challenges and promising future research directions that could advance high-performance, intelligent, and multifunctional THz optoelectronics based on electrically tunable 2D quantum materials.