The first metal-shrouded two-dimensional semiconductor, single-layer Tl2O, is discussed from first principles. It is thermally and dynamically stable, has a low cleavage energy calling for exfoliation from layered Tl2O bulk, and has a very small interface mismatch compared to (001) Tl metal. Single-layer Tl2O exhibits a direct bandgap of 1.56 eV and a very high charge carrier mobility of 4.3 × 103 cm2 V-1 s-1. The metal-shrouded 2D semiconductor promises interesting applications in 2D electronics. An intriguing layer-thickness-dependent direct-to-indirect bandgap transition is observed, and contrary to early literature, the bulk is also a semiconductor.
Bibliographical noteFunding Information:
Financial support by the Deutsche Forschungsgemeinschaft FLAG-ERA (HE 3543/27-1) and computer time at ZIH Dresden are gratefully acknowledged. We thank Prof. Udo Schwingenschlögl and Dr. Vladimir Bač ́ for inspiring discussions. We thank Dr. M. Franchini for help on Bader calculations.
© 2017 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry