Observation and theoretical analysis of near-infrared luminescence from CVD grown lanthanide Er doped monolayer MoS2 triangles

Abstract

The near-infrared (NIR) emission of Er3+ ions has been extensively studied owing to their significance in optical communication applications. However, studies concerning the incorporation of lanthanide ions into the two-dimensional (2D) matrix are still in the early stages. In this work, we developed an ingenious two-step vapor-phase-transfer method to synthesize Er3+ doped MoS2 single-crystalline monolayers. The NIR emission at 1530 nm was observed from the doped MoS2 nanosheets under 980 nm diode laser excitation, corresponding to the energy transition from 4I13/2 to 4I11/2 of the Er3+ dopant. The concentration quenching effect was demonstrated with an optimal Er content of around 4 mol. %. To further understand the effect of lanthanide doping on the 2D MoS2 host matrix in terms of the growth mechanism and electronic structures, theoretical analysis was performed on Er-doped monolayer MoS2 using the density functional theory calculation. The computed band structure with the superimposed Dieke diagram was in good accordance with our experimental results. Our work offers the possibility to develop doping strategies in the 2D limit and provides an in-depth understanding of the lanthanide doping in atomically thin materials.