Temperature-Driven α-β Phase Transformation and Enhanced Electronic Property of 2H α-In₂Se₃

In recent years, thin layered indium selenide (In2Se3) has attracted rapidly increasing attention due to its fascinating properties and promising applications. Here, we report the temperature-driven α-β phase transformation and the enhanced electronic property of 2H α-In2Se3. We find that 2H α-In2Se3 transforms to β-In2Se3 when it is heated to a high temperature, and the transformation temperature increases from 550 to 650 K with the thickness decreasing from 67 to 17 nm. Additionally, annealing the sample below the phase transformation temperature can effectively improve the electronic property of a 2H α-In2Se3 field-effect transistor, including increasing the on-state current, decreasing the off-state current, and improving the subthreshold swing. After annealing, not only the contact resistance decreases significantly but also the mobility at 300 K increases more than 2 times to 45.83 cm2 V–1 s–1, which is the highest among the reported values. Our results provide an effective method to improve the electrical property and the stability of the In2Se3 nanodevices.