title: Unravelling a simple method for the low temperature synthesis of silicon nanocrystals and monolithic nanocrystalline thin films.
abstract: In this work, we present new results on the plasma processing and structure of hydrogenated polymorphous silicon (pm-Si:H) thin films. pm-Si:H thin films consist of a low volume fraction of silicon nanocrystals embedded in a silicon matrix with medium range order, and they possess this morphology as a significant contribution to their growth comes from the impact on the substrate of silicon clusters and nanocrystals synthesized in the plasma. Quadrupole mass spectrometry, ion flux measurements, and material characterization by transmission electron microscopy (TEM) and atomic force microscopy all provide insight on the contribution to the growth by silicon nanocrystals during PECVD deposition. In particular, cross-section TEM measurements show for the first time that the silicon nanocrystals are uniformly distributed across the thickness of the pm-Si:H film. Moreover, parametric studies indicate that the best pm-Si:H material is obtained at the conditions after the transition between a pristine plasma and one containing nanocrystals, namely a total gas pressure around 2 Torr and a silane to hydrogen ratio between 0.05 to 0.1. From a practical point of view these conditions also correspond to the highest deposition rate achievable for a given RF power and silane flow rate.
authors.affiliation: KIER-UNIST Advanced Center for Energy, Korea Institute of Energy Research, 44919, Ulsan, South Korea.|LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France.|TOTAL New Energies, 92069 Paris, France.
authors.forename: Ka-Hyun
authors.initials: KH
authors.lastname: Kim
authors.affiliation: LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France.
authors.forename: Erik V
authors.initials: EV
authors.lastname: Johnson
authors.affiliation: Faculty of Physics, Moscow State University, Moscow, 119991, Russia.
authors.forename: Andrey G
authors.initials: AG
authors.lastname: Kazanskii
authors.affiliation: Faculty of Physics, Moscow State University, Moscow, 119991, Russia.
authors.forename: Mark V
authors.initials: MV
authors.lastname: Khenkin
authors.affiliation: LPICM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau, France.
authors.forename: Pere
authors.initials: P
authors.lastname: Roca I Cabarrocas