TY - JOUR
T1 - Characterization of nano-porosity in molecular layer deposited films
AU - Perrotta, A.
AU - Poodt, Paul
AU - van den Bruele, Fieke J.
AU - Kessels, W.M.M.
AU - Creatore, M.
PY - 2018/5/1
Y1 - 2018/5/1
N2 - Molecular layer deposition (MLD) delivers (ultra-) thin organic and hybrid materials, with atomic-level thickness control. However, such layers are often reported to be unstable under ambient conditions, due to the interaction of water and oxygen with the hybrid structure, consequently limiting their applications. In this contribution, we investigate the impact of porosity in MLD layers on their degradation. Alucone layers were deposited by means of trimethylaluminium and ethylene glycol, adopting both temporal and spatial MLD and characterized by means of FT-IR spectroscopy, spectroscopic ellipsometry, and ellipsometric porosimetry. The highest growth per cycle (GPC) achieved by spatial MLD resulted in alucone layers with very low stability in ambient air, leading to their conversion to AlOx. Alucones deposited by means of temporal MLD, instead, showed a lower GPC and a higher ambient stability. Ellipsometric porosimetry showed the presence of open nano-porosity in pristine alucone layers. Pores with a diameter in the range of 0.42-2 nm were probed, with a relative content between 1.5% and 5%, respectively, which are attributed to the temporal and spatial MLD layers. We concluded that a correlation exists between the process GPC, the open-porosity relative content, and the degradation of alucone layers.
AB - Molecular layer deposition (MLD) delivers (ultra-) thin organic and hybrid materials, with atomic-level thickness control. However, such layers are often reported to be unstable under ambient conditions, due to the interaction of water and oxygen with the hybrid structure, consequently limiting their applications. In this contribution, we investigate the impact of porosity in MLD layers on their degradation. Alucone layers were deposited by means of trimethylaluminium and ethylene glycol, adopting both temporal and spatial MLD and characterized by means of FT-IR spectroscopy, spectroscopic ellipsometry, and ellipsometric porosimetry. The highest growth per cycle (GPC) achieved by spatial MLD resulted in alucone layers with very low stability in ambient air, leading to their conversion to AlOx. Alucones deposited by means of temporal MLD, instead, showed a lower GPC and a higher ambient stability. Ellipsometric porosimetry showed the presence of open nano-porosity in pristine alucone layers. Pores with a diameter in the range of 0.42-2 nm were probed, with a relative content between 1.5% and 5%, respectively, which are attributed to the temporal and spatial MLD layers. We concluded that a correlation exists between the process GPC, the open-porosity relative content, and the degradation of alucone layers.
UR - http://www.scopus.com/inward/record.url?scp=85048441800&partnerID=8YFLogxK
U2 - 10.1039/C8DT01246F
DO - 10.1039/C8DT01246F
M3 - Article
C2 - 29796504
AN - SCOPUS:85048441800
SN - 1477-9226
VL - 47
SP - 7649
EP - 7655
JO - Dalton Transactions
JF - Dalton Transactions
IS - 23
ER -