Dielectric-Induced Charge Doping in Monolayer MoS2.

Unintentional doping from dielectrics can impact the electronic properties of two-dimensional transition metal dichalcogenide (2D TMD) semiconductors. Our recent work shows that high-dielectric-constant (k) ZrO2 is an electrostatically inert dielectric for 2D MoS2, supported by X-ray spectroscopy (XPS) and electrical measurements. Here, we expand this work through gate-controlled photoluminescence (PL) of monolayer MoS2 placed on different substrates. MoS2 on ZrO2 exhibits a low carrier concentration, indicated by a small trion-to-exciton ratio (X-/X0) of 0.5, similar to those on high-quality hBN. At a high electrostatic doping of ∼1013 cm-2, MoS2 on high-k ZrO2 reveals a slight exponential dependence of X-/X0 versus carrier concentration, while MoS2 on SiO2 shows strong exponential characteristics even at low gating (1012 cm-2) due to substantial electron doping from substrate-induced disorder tail states. Our findings provide insights into the doping mechanisms in industry-compatible amorphous dielectrics and evaluate their potential for scalable optoelectronic devices.