Control of nucleation density of 2D α-GeTe nanosheets with ferroelectric properties

In this work, we systematically investigated temperature and time of substrate pre-annealing on the growth of GeTe nanosheets by chemical vapor deposition. It was found that thermal annealing in air was a useful way to reduce the density of nucleation site. As a result, the lateral size of nanosheets increased from ∼5 μm to ∼30 μm by increasing the temperature of pre-annealing. Meanwhile, the increasement of pre-annealing time increased lateral size from ∼5 μm to ∼28 μm. Furthermore, α-GeTe nanosheets hold room-temperature ferroelectric properties. This provides an effective method to control the growth of 2D ferroelectric materials on mica.