Transparent conductive oxide water etching revealed by operando spectroscopy

Perovskite transition metal oxide thin films exhibit a wide range of functional properties that make them promising candidates for electronic devices. In their transparent conductive oxide (TCO) form, they possess a unique combination of high electrical conductivity and visible-range optical transparency. Among the TCOs, SrVO3 (SVO) has gained significant attention due to its electrical and optical properties comparable to the most commonly used indium-tin-oxide (ITO), which suffers from high costs due to the scarcity of indium. However, SVO is prone to surface chemical degradation over time, which poses a significant challenge. This degradation leads to the segregation of Sr towards the surface and the over-oxidization of V, resulting in the formation of a thin insulating layer at the TCO surface. A full understanding and control of these issues are needed to overcome its use in large-scale technology.

In our study we have used pulsed laser deposition (PLD) technique to deposit polycrystalline SVO film of few tens nanometers on top of a Si substrate, which is also suitable for further industrial transfer. To simulate the aging process, we subjected the SVO films to ex situ annealing treatments in air at 200°C, a well-established procedure Subsequently, we performed spectroscopic measurements using x-ray photoemission and x-ray absorption techniques under ultra-high vacuum conditions to characterize the samples. All spectroscopic characterizations were carried out at the APE-HE beamline of Elettra, partly in the framework of the Nanoscience Foundry and Fine Analysis (NFFA-MUR Italy Progetti Internazionali) facility.

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