2D MoTe₂ CMOS Circuits and Photodiodes by Contact Engineering

Abstract Precisely controlling charge‐carrier polarity in 2D materials is crucial for high‐performance complementary circuits. With its moderate bandgap, 2H‐MoTe₂ enables tunable electron and hole injection, but stable n‐type conduction using low‐work‐function contacts without encapsulation has remained challenging. Here, a simple method is demonstrated to achieve stable n‐type polarity in 2H‐MoTe₂ using semimetallic Bi contacts. The n‐type behavior remains air‐stable without encapsulation, as DFT calculations reveal minimal metal‐induced gap states, allowing the Fermi level to shift near the conduction band. The n‐channel MoTe₂ devices achieve a maximum on‐state current of 18 µA and a high electron mobility of 64 cm² V⁻¹s ⁻¹. By integrating n‐type MoTe₂ with Bi contacts and p‐type MoTe₂ with Au contacts, CMOS inverters, NOR, and NAND gates are realized, with the inverter showing a high DC voltage gain of 51. Additionally, a MoTe₂ p–n diode exhibits strong rectification (ratio ≈1.1 × 10⁴, ideality factor 1.07) and excellent broadband photoresponse. Under 900 nm light at 0.046 mW cm⁻², it achieves a responsivity of 0.25 A/W and detectivity of 6.3 × 10¹⁰ Jones. This work enables MoTe₂‐based complementary circuits and photodiodes using only different contacts, simplifying 2D IC and optoelectronic device fabrication.