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

Abstract 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 cm 2 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 (NO 2 )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 (H 2 S) 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.