7/13/2023 0 Comments Core shell atomic layer depositionThe formation of Al-F and MoOF4 seem to initially form, but after H2S is introduced sulfate species begin to appear. The nucleation and early stages of MoS2 ALD on metal oxide surfaces were investigated using in situ Fourier transform infrared (FTIR) spectroscopy. The deposited films were amorphous, and after annealing in hydrogen, crystalline MoS2 was discernable. in situ quartz crystal microbalance measurements were used to demonstrate self-limiting chemistry for both precursors, which is the hallmark of ALD. We demonstrate the first ALD of MoS2 at 200 ℃ using molybdenum hexafluoride (MoF6), a liquid at room temperature, and hydrogen sulfide (H2S). Atomic layer deposition (ALD) has been used to grow amorphous films of MoS2 using molybdenum chlorides and carbonates, however many of these molybdenum chemistries require high temperature vapor transport as they are solids at room temperature. While bulk MoS2 is an indirect band gap semiconductor with a band gap of ~1.3 eV, monolayer MoS2 exhibits a direct band gap of ~1.8 eV, which is an attractive property for many opto-electronic applications. The weak secondary bonding allows for isolation of these 2D materials to single layers, like graphene. Like graphite, it has a layered structure containing weak van der Waals bonding between layers, while exhibiting strong covalent bonding within layers. ![]() ![]() Molybdenum disulfide (MoS2) is the prototypical two-dimensional (2D) semiconductor.
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