High-Performance MoTe2/TFLN Waveguide-Integrated Photo-field-effect Transistors

Thin-film lithium niobate (TFLN) is a key platform for next-generation integrated photonics, enabled by its excellent optical properties, low propagation loss, and strong optical field confinement. However, its wide bandgap and weak optical absorption severely restrict direct photodetection, necessitating heterogeneous integration with highly photosensitive materials. Here, we report a high-performance waveguide-integrated MoTe2 photo-field-effect transistor (Photo-FET) on a TFLN platform enabled by heterogeneous integration. Benefiting from gate-voltage modulation, the device exhibits excellent optoelectronic performance, achieving an ultralow dark current of ∼180 pA at a positive gate voltage and a drain-source voltage of -1 V, nearly three orders of magnitude lower than that of the ungated device. Under 1310 nm illumination, the Photo-FET demonstrates a high responsivity of 13 A/W (15.4 nW), a large on/off ratio of 4 × 104, rise and fall times of 467 and 533 μs, respectively, and a high detectivity of 1.3 × 1013 W-1. This hybrid MoTe2/TFLN Photo-FET architecture enables low-noise, high-sensitivity operation, offering a promising route toward telecommunication-band photodetection in integrated photonic systems.