Multifunctional 2H-MoTe₂ Device Enabling Broadband Self-Powered Photodetection and On-Chip Miniaturized Spectrometry

Controlling carrier polarity in 2D semiconductors is essential for complementary electronics but is hindered by Fermi-level pinning. Here, we demonstrate contact engineering in 2H-MoTe₂ using high-work-function Pt and low-work-function Bi to realize p-type and n-type field-effect transistors. An asymmetric Pt/2H-MoTe₂/Bi configuration enables a self-powered broadband photodetector with a 430-1400 nm response, a maximum responsivity of 1.06 A/W, and a detectivity of 1.86 × 10¹² Jones. The device exhibits fast photoresponse (7.53 µs for rise time and 2.39 µs for fall time) and a cutoff frequency > 50 kHz, allowing real-time near-infrared optical communication via ASCII-encoded binary signals. Integrating the same architecture with computational spectroscopy algorithms yields a miniaturized spectrometer (430-1400 nm), achieving 5 nm spectral resolution at ≤ 1 V drain bias. This unified, low-power, and high-speed platform demonstrates broadband spectral reconstruction and color imaging, highlighting the potential of contact-engineered 2D semiconductors for next-generation on-chip spectroscopy and optical communication.