Tip-enhanced photoluminescence of monolayer MoS₂ increased and spectrally shifted by injection of electrons

Abstract Using tip-enhanced photoluminescence (TEPL), we investigate micron-size monolayer MoS 2 flakes. In a sequence of studies, apply various voltages between the Ag-coated nano-tip and flakes observe an intriguing result. During TEPL measurement, that spectrum is blue shifted overall signal intensity increased. We attribute this behavior to plasmon-induced electron injection into . Additionally, when tip negatively biased with respect sample during nonuniform images containing defects are gradually changed be uniform reach saturation. verify saturation state in can last over half year.