Multifunctional 2H‐MoTe ₂ 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‐MoTe 2 using high‐work‐function Pt and low‐work‐function Bi to realize p‐type and n‐type field‐effect transistors. An asymmetric Pt/2H‐MoTe 2 /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 × 10 12 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.