monolayer

We study the binding energies of negatively (two electron and one hole) and positively (one electron and two holes) charged trions in suspended two-dimensional monolayer of WSe₂ in the framework of effective-mass model by employing the method of hyperspherical harmonics in configuration space [1,2]. The binding energies of trions are calculated using the Ritova-Keldysh potential. Trion fine structure based on formation of intravalley trions in spin singlet (S=1/2) state and intervalley trions in triplet (S=3/2) state is addressed. Our calculations show that those state are stables. To understand the importance of dielectric screening on the formation of trions, we perform calculations of the binding energy for WSe₂ placed in three different dielectric environments: supported on an SiO₂ substrate, supported on an h-BN substrate, and encapsulated by h-BN, and compare these results with the case of suspended WSe₂ binding energy. The analysis and comparison of our results for the binding energies of trions with those calculated via different theoretical methods and experimental data are presented.

1. R. Ya. Kezerashvili, Sh. M. Tsiklauri, Few Body Syst.58, (18) 1–5 (2017).
2. I. Filikhin, R. Ya. Kezerashvili, Sh. M. Tsiklauri, B. Vlahovic, Nanotechnology 29, 124002 (2018).