Photo-thermal origin of pulse laser induced orientation of crystallographic c axis in Tellurium thin films

Abstract

Recent studies have shown that the orientation of crystallographic c axis of Tellurium thin films can be controlled using picosecond long laser pulses. This method provides spatially programmable control of the crystal orientation and is therefore highly attractive for practical applications in functional optical and electronic devices. Previously, it was suggested that laser-induced selective melting and recrystallization can cause the laser-induced reorientation. However, this interpretation remains inconclusive due to limited data. To clarify the mechanism, here we systematically study Te samples under different irradiation conditions. We find that the threshold fluence for inducing optical reorientation depends on the number of laser pulses. The results agrees well with a minimal kinetic model based on the Arrhenius law. Using the model developed, we investigate the condition required to control the optic axis in other two-dimensional materials, such as black phosphorus, WTe2, and SnSe. These findings provide a guide for developing functional electro-optical devices based on anisotropic materials.