Preparation and photoelectric properties of SnTe nanofilm

As a topological crystal insulator, tin telluride (SnTe) has unique properties that are different from those of traditional topological insulators. Due to its helical multi-surface states, strong topological protection characteristics, gapless topological surface states, narrow bulk band gap, high mobility at room temperature and other excellent properties, SnTe has a great application potential in photodetectors with minimal energy consumption, broad spectrum and ultra-fast response. However, the preparation of large area high quality SnTe nanofilms is still a big challenge. Here, we report a facile and efficient preparation method for large area SnTe nanofilm (2 cm ×2 cm) by RF magnetron sputtering method. The nanofilm having a thickness of 5.8 nm and surface roughness of 0.51 nm was obtained. Moreover, the prepared nanofilm was crystallized without annealing treatment and exhibited uniform surface. The photoconductive prototype device based on the SnTe nanofilm demonstrated a significant photoelectric response under an illumination of 365, 555 and 850 nm light source at room temperature. Furthermore, the ultraviolet, visible and near infrared photoelectric performance of the device remained stable even after six months in the atmosphere of the drying cabinet. These results indicate that the SnTe nanofilm has potential applications in broad spectrum photodetectors.