Bandgap control in two-dimensional semiconductors via coherent doping of plasmonic hot electrons

• Published in: Nature communications Vol. 12; no. 1; pp. 4332 - 8
• Main Authors: Chen, Yu-Hui, Tamming, Ronnie R., Chen, Kai, Zhang, Zhepeng, Liu, Fengjiang, Zhang, Yanfeng, Hodgkiss, Justin M., Blaikie, Richard J., Ding, Boyang, Qiu, Min
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.07.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/357/1018; 639/624/400/1021; 639/624/400/2797; Coherence; Conduction bands; Coupling; Current carriers; Design optimization; Doping; Energy gap; Excitons; Hot electrons; Humanities and Social Sciences; Monolayers; multidisciplinary; Optoelectronic devices; Plasmonics; Population inversion; Room temperature; Science; Science (multidisciplinary); Self-assembly; Semiconductors; Tungsten; Tungsten disulfide
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-24667-8

Bandgap control is of central importance for semiconductor technologies. The traditional means of control is to dope the lattice chemically, electrically or optically with charge carriers. Here, we demonstrate a widely tunable bandgap (renormalisation up to 550 meV at room-temperature) in two-dimensional (2D) semiconductors by coherently doping the lattice with plasmonic hot electrons. In particular, we integrate tungsten-disulfide (WS 2 ) monolayers into a self-assembled plasmonic crystal, which enables coherent coupling between semiconductor excitons and plasmon resonances. Accompanying this process, the plasmon-induced hot electrons can repeatedly fill the WS 2 conduction band, leading to population inversion and a significant reconstruction in band structures and exciton relaxations. Our findings provide an effective measure to engineer optical responses of 2D semiconductors, allowing flexibilities in design and optimisation of photonic and optoelectronic devices. The established means of bandgap control in semiconductors are based on chemical, electrical or optical doping. Here, the authors report wide bandgap modulations in monolayer WS2 at room temperature by coupling the 2D semiconductor to a self-assembled plasmonic crystal inducing coherent hot electron doping.