Enhanced Crystallinity of P-Type 2D Tellurium Thin Films by Pulsed Laser Annealing Process and Its Applications on High-Performance Photodetectors and High-Sensitivity Gas Sensors

Here, a pulsed laser annealing (PLA) process is employed to enhance the crystallinity and functional performance of tellurium (Te) thin-film devices. The PLA facilitates localized melting followed by rapid cooling, which promotes recrystallization while significantly reducing energy loss compared to conventional thermal annealing techniques. Field-effect transistors (FETs) incorporating a PLA-treated Te film (10 nm) demonstrate a hole mobility of 107.9 cm² V⁻¹ s⁻¹ and a substantially improved on/off current ratio, underscoring their suitability for high-performance electronic applications. Photodetectors based on the PLA-treated Te film (10 nm) exhibit exceptional photoresponsivity of 72.94 A W⁻¹ under light illumination with a wavelength of 408 nm, along with faster response time and improved detectivity, reflecting their enhanced optoelectronic functionality. For gas sensing measurements, PLA-treated Te (10 nm) sensors achieve a nitrogen dioxide (NO₂)response of 55.4% at 1 ppm, with rapid response and recovery times of 0.92 and 27.7 s, respectively. For detecting hydrogen sulfide (H₂S) gas, the response improves to 98.3% at 10 ppm, with response and recovery times of 121.3 and 78.8 s. These improvements are attributed to the enhanced crystallinity, enlarged grain sizes, and smoother surface morphology induced by the PLA process.