Nucleation Behavior-Morphology-Resistivity of Atomic Layer Deposited Pt on Atomic Layer Deposited Yttria-Stabilized Zirconia Films

Abstract

The nucleation behavior, morphology, and resistivity of atomic layer deposited (ALD) Pt on yttria-stabilized zirconia (YSZ) films have been investigated under different YSZ surface conditions. The YSZ was prepared by ALD as well using the same reactor as that for subsequent Pt ALD and the YSZ surface properties were modified by thermal annealing prior to Pt ALD. Annealing of YSZ at 800°C for 5 min in N2 yielded a cubic polycrystalline surface having high hydrophilicity and surface roughness compared to that of as-deposited YSZ. The annealed polycrystalline YSZ film had four times higher Pt nucleation site density (∼13000/μm2) after 15 Pt ALD cycles and exhibited Pt coalescence after only about 40 cycles. With annealing, the resulting surface conditions of YSZ strongly enhance subsequent ALD Pt and in this study an interconnected mesoporous morphology of ALD Pt with low resistivity (∼13 μΩ·cm) was achieved with only 80 Pt ALD cycles on annealed polycrystalline YSZ surfaces which is ideal for gas permeable Pt applications such as electrode in solid oxide fuel cells.