Tellurene: A Multifunctional Material for Midinfrared Optoelectronics

The mid-infrared spectral band (2–20 μm) is of significant technological importance for thermal imaging, spectroscopic sensing, and free-space communications. Lack of optical materials compatible with common semiconductor substrates, however, presents a standing hurdle for integrated photonic device development in the mid-infrared domain. Tellurene, atomically thin crystals of elemental tellurium, is an emerging 2-D material amenable to scalable solution-based synthesis. It uniquely combines small and tunable bandgap energies, high carrier mobility, exceptionally large electro-optic activity, and superior chemical stability, making it a promising and versatile material platform for mid-infrared photonics. With these material properties in mind, we propose and design a waveguide-integrated tellurene photodetector and Pockels effect modulator. The photodetector boasts a record room temperature noise equivalent power of 0.03 fW/Hz1/2 at 3 μm wavelength, while the optimized modulator device claims a half-wave voltage-length product (V π·L) of 2.7 V·cm and a switching energy of 12.0 pJ/bit, both representing substantial improvements to current state-of-the-art devices.