Low-Temperature Growth of Centimeter-Sized 2D PdSe 2 by Self-Limiting Liquid-Phase Edge Epitaxy

Two-dimensional (2D) PdSe 2 atomic crystals hold great potential for optoelectronic applications due to their bipolar electrical characteristics, tunable bandgap, high electron mobility, and exceptional air stability. Nevertheless, the scalable synthesis of large-area, high-quality 2D PdSe 2 crystals using chemical vapor deposition (CVD) remains a significant challenge. Here, we present a self-limiting liquid-phase edge-epitaxy (SLE) low-temperature growth method to achieve high-quality, centimeter-sized PdSe 2 films with single-crystal domain areas exceeding 30 μm. The SLE growth mechanism, clarified by theoretical calculations and time-of-flight secondary ion mass spectrometry (ToF-SIMS), reveals that hydrogen ions on the precursor surface inhibit vertical growth while promoting lateral growth. The as-grown PdSe 2 few-layer exhibits a surface roughness of 1.20 nm and an average conductivity of 1.67 × 10 –6 S/m, demonstrating their smoothness and uniformity. Temperature-dependent electrical measurements and transfer characteristic curves confirm the orthorhombic PdSe 2 ’s bipolar semiconductor behavior. The photodetector based on few-layer PdSe 2 films exhibit excellent optoelectronic performance in the 405–1650 nm wavelength range, achieving a responsivity of 6262.37 A W –1, a detectivity of ∼10 12 Jones under 1064 nm illumination, and a fast response time of 37.1 μs, making them highly suitable for broadband photodetection applications. This work provides valuable insights into the scalable synthesis of PdSe 2 few-layers and establishes a foundation for the development of PdSe 2 -based integrated functional devices.