Atomic layer deposition of self-assembled aluminum nanoparticles using dimethylethylamine alane as precursor and trimethylaluminum as an initiator

Our research provided a way to produce earth-abundant plasmonic nanoparticles with a well-defined orientation (111) for energy materials and nanosensing applications. In the atomic layer deposition (ALD) of aluminum nanoparticles, dimethylethylamine alane (DMEAA; AlH3N(CH3)2(CH2CH3)) has been employed as a processor of the aluminum source, while trimethylaluminum (TMA) as a growth initiator. We studied the morphology of self-assembled aluminum nanoparticle growth with the ALD process by passivating TMA on a silicon surface with previously absorbed hydroxyl groups. The reaction mechanism was proposed for the dissociation of the initiator (TMA), the precursor (DMEAA), and the effect of each one of them on the particle size by analyzing the obtained morphologies. Our results led us to theorize that to initiate the nucleation and the growth of aluminum nanoparticles, a conductive source of electrons is required such as TMA. We discussed the growth of aluminum nanoparticles as well as morphology step by step through SEM images. The observations showed that tetrahedrons of aluminum nanoparticles continue growing to octahedrons. The XRD analysis confirmed the orientation of aluminum nanoparticles in (111), in addition to obtaining their crystallinity information in-depth. This approach could allow for further development of new controlled morphologies and increase the knowledge in the growth of earth-abundant plasmonic nanoparticles.