MoS₂ Functionalization for Ultra-Thin Atomic Layer Deposited Dielectrics


The effect of room temperature ultraviolet-ozone (UV-O₃) exposure of MoS₂ on the uniformity of subsequent atomic layer deposition of Al₂O₃ is investigated. It is found that a UV-O₃ pre-treatment removes adsorbed carbon contamination from the MoS₂ surface and also functionalizes the MoS₂ surface through the formation of a weak sulfur-oxygen bond without any evidence of molybdenum-sulfur bond disruption. This is supported by first principles density functional theory calculations which show that oxygen bonded to a surface sulfur atom while the sulfur is simultaneously back-bonded to three molybdenum atoms is a thermodynamically favorable configuration. The adsorbed oxygen increases the reactivity of MoS₂ surface and provides nucleation sites for atomic layer deposition of Al₂O₃. The enhanced nucleation is found to be dependent on the thin film deposition temperature.



Gigaelectronvolts (GeV), Special relativity (Physics), Dielectrics, Molybdenum disulfide


©2014 AIP Publishing LLC


Azcatl, Angelica, Stephen McDonnell, K. C. Santosh, Xin Peng, et al. 2014. "MoS2 functionalization for ultra-thin atomic layer deposited dielectrics." Applied Physics Letters 104(111601): 1-4.