Phase-Engineering-Driven Enhanced Electronic and Optoelectronic Performance of Multilayer In₂Se₃ Nanosheets

Here, we report electronic and optoelectronic performance of multilayer In₂Se₃ are effectively regulated by phase engineering. The electron mobility is increased to 22.8 cm² V^-1 s^-1 for β-In₂Se₃ FETs, which is 18 times higher than 1.26 cm² V^-1 s^-1 of α-In₂Se₃ FETs. The enhanced electronic performance is attributed to larger carrier sheet density and lower contact resistance. Multilayer β-In₂Se₃ photodetector exhibits an ultrahigh responsivity of 8.8 × 10⁴ A/W under 800 nm illumination, which is 574 times larger than 154.4 A/W of α-In₂Se₃ photodetector. Our results demonstrate phase-engineering is a valid way to tune and further optimize electronic and optoelectronic performance of multilayer In₂Se₃ nanodevices.