Doped van der Waals heterostructures host layer-hybridized trions, i.e. charged excitons with layer-delocalized constituents holding promise for highly controllable optoelectronics. Combining a microscopic theory with photoluminescence (PL) experiments, we demonstrate the electrical tunability of the trion energy landscape in naturally stacked WSe2 bilayers. We show that an out-of-plane electric field modifies the energetic ordering of the lowest lying trion states, which consist of layer-hybridized Λ-point electrons and layer-localized K-point holes. At small fields, intralayer-like trions yield distinct PL signatures in opposite doping regimes characterized by weak Stark shifts in both cases. Above a doping-asymmetric critical field, interlayer-like species are energetically favored and produce PL peaks with a pronounced Stark red-shift and a counter-intuitively large intensity arising from efficient phonon-assisted recombination. Our work presents an important step forward in the microscopic understanding of layer-hybridized trions in van der Waals heterostructures and paves the way towards optoelectronic applications based on electrically controllable atomically-thin semiconductors.
@article{arxiv.2404.18716,
title = {Electrically tunable layer-hybridized trions in doped WSe$_2$ bilayers},
author = {Raul Perea-Causin and Samuel Brem and Fabian Buchner and Yao Lu and Kenji Watanabe and Takashi Taniguchi and John M. Lupton and Kai-Qiang Lin and Ermin Malic},
journal= {arXiv preprint arXiv:2404.18716},
year = {2024}
}