title: Semiconductor-to-metal transition in the bulk of WSe2upon potassium intercalation.
abstract: We present electron energy-loss spectroscopic measurements of potassium (K) intercalated tungsten diselenide (WSe2). After exposure of pristine WSe2films to potassium, we observe a charge carrier plasmon excitation at about 0.97 eV, which indicates a semiconductor-to-metal transition. Our data reveal the formation of one particular doped K-WSe2phase. A Kramers-Kronig analysis allows the determination of the dielectric function and the estimation of the composition of K0.6WSe2. Momentum dependent measurements reveal a substantial plasmon dispersion to higher energies.
authors.affiliation: IFW Dresden, D-01069 Dresden, Germany. Department of Physics, COMSATS Institute of Information Technology, Park Road, 45550 Islamabad, Pakistan.
authors.forename: Mushtaq
authors.initials: M
authors.lastname: Ahmad
authors.forename: Eric
authors.initials: E
authors.lastname: Müller
authors.forename: Carsten
authors.initials: C
authors.lastname: Habenicht
authors.forename: Roman
authors.initials: R
authors.lastname: Schuster
authors.forename: Martin
authors.initials: M
authors.lastname: Knupfer
authors.forename: Bernd
authors.initials: B
authors.lastname: Büchner