Rapid Solid-Phase Sulfurization Growth and Nonlinear Optical Characterization of Transfer-Free TiS3 Nanoribbons

Quasi-1D titanium trisulfide (TiS3) has strong in-plane anisotropy with a direct band gap of about 1 eV, which has attracted wide attention in the fields of microelectronics and optoelectronics. However, the investigation of in situ synthesis, synthetic mechanism, and nonlinear optical properties of TiS3 is rarely reported. In this work, we developed a transfer-free method to grow TiS3 nanoribbons, successfully reducing the synthesis time from a few days to less than 24 h without pretreatment. Raman spectroscopy revealed TiS3 was not directly synthesized by titanium (Ti) and sulfur (S) but by the further sulfurization reaction of intermediate product TiS2. Moreover, the polarized four-wave mixing (FWM) imaging of the as-grown TiS3 samples was conducted by ultrafast nonlinear optical spectroscopy for the first time, identifying the crystal axis orientation of TiS3 accurately and quickly. Our work not only provides a rapid growth method for transfer-free synthesis of TiS3 nanoribbons on SiO2/Si substrates but also investigate the fast and non-destructive ultrafast nonlinear optical characterization of quasi-1D TiS3, which lays a foundation for understanding the synthetic mechanism and physicochemical properties of transition metal trisulfides (TMTCs) and promoting the functional device applications of TMTCs represented by TiS3.