Unraveling the Augmented Field Emission Performance of Molybdenum Disulfide‐Praseodymium Sulfide (MoS₂@PrS) Heterostructure: A Combined Experimental and First Principles‐Based Study

The molybdenum disulfide-praseodymium sulfide (MoS₂-PrS) heterojunctions are optimally synthesized through a sophisticated three-step procedure. Initially, MoS₂ rods are synthesized using the micellar route followed by a solid-state reaction, forming well-defined structures. Subsequently, PrS nanoparticles are synthesized using the same method. In the final stage, PrS nanoparticles are evenly self-assembled onto the MoS₂ rods to create MoS₂-PrS heterojunctions. This is accomplished using a combination of polyethylene glycol and ethanol as a cohesive substance, assisted by the spin coating process. The MoS₂-PrS heterostructure has exceptional field emission characteristics, with a much lower turn-on field of 2.6 V µm^-1. This is in sharp contrast to the turn-on fields of 3.5 and 4.3 V µm^-1 reported in pure MoS₂ and PrS, respectively. The emission current demonstrates remarkable stability at a predetermined value of 6 V µm^-1 across 8 h, with variations limited to within ±2% of the mean value. The improved field emission (FE) capability of the MoS₂-PrS heterostructure is attributed to its high enhancement factor (β) of 2.1 × 10³. The results highlight the capability of the MoS₂-PrS heterostructure emitter as a promising electron source in vacuum nano/microelectronic systems. Density functional theory calculation on electronic structure is performed to support the experimental results.