Physical Vapor Deposition\nof High-Mobility P‑Type\nTellurium and Its Applications for Gate-Tunable van der Waals PN Photodiodes

Recently, tellurium has attracted resurgent interest\ndue to its\noutstanding p-type characteristics and ambient environmental stability.\nHere, we present a substrate engineering-based physical vapor deposition\nmethod to synthesize high-quality Te nanoflakes and achieved a field-effect\nhole mobility of 1450 cm<sup>2</sup>/(V s), which is, to the best\nof our knowledge, the highest among existing synthesized two-dimensional\np-type semiconductors. The high mobility of Te enables the fabrication\nof Te/MoS<sub>2</sub> PN diodes with highly gate-tunable characteristics.\nThe Te/MoS<sub>2</sub> heterostructure is demonstrated to be used\nas visible-light photodetectors with a current responsivity up to\n630 A/W, which is about 1 order of magnitude higher than one achieved\nusing p-type Si-MoS<sub>2</sub> PN photodiodes. The photoresponse\nof Te/MoS<sub>2</sub> heterojunctions also exhibits strong gate tunability\ndue to their ultrathin thickness and unique band alignment. The successful\nsynthesis of high-mobility Te and its integration into Te/MoS<sub>2</sub> photodiodes show promise for the development of highly tunable\nand multifunctional photodetectors.