Self-powered SnSe photodetectors fabricated by ultrafast laser

Photodetectors are highly desirable in optoelectronic applications such as optical sensing and wearable electronics. Two-dimensional (2D) materials have attracted attention for next-generation optoelectronics because of their extraordinary electrical transport and optical properties. However, traditional photodetectors generally need high external bias which limits the practical application. Here, we propose a concept of ultrafast laser-fabricated tin selenide (SnSe) thin films for self-powered photoelectric devices. Laser-induced periodic surface structures (LIPSSs) were successfully introduced in the SnSe films which mainly arose from the interference between incident laser pulses and oscillating electrons, and excessive electron densities resulted in material ablation. The LIPSSs resulted in an enhanced optical absorption compared with that of the unprocessed film. The regulation of surface absorption offered a temperature gradient that was essential for hot carriers flow under the photothermoelectric effect. The experimental studies demonstrate that the ultrafast laser-fabricated SnSe photoelectric devices possessed a high infrared response without external bias. This work provides a strategy for the design of photoelectric devices such as photodetectors using thermoelectric materials and expands the knowledge on laser-material interactions for optoelectronics applications.