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Project Summary: Understanding surface stability is critically important as 2D materials like SnSe are developed
for piezoelectric and optical applications. SnSe is a candidate piezoelectric material in the monolayer, but many chalcogenide thin films undergo severe oxidation upon removal to atmosphere, rendering them unsuitable for their original purposes. In this study, SnSe films were grown by molecular beam epitaxy and exposed to atmosphere for two years. Immediately upon removal from the MBE system, the films exhibit an oxide layer with thickness less than 3.5 nm. However, further degradation does not occur despite the propensity of Sn to oxidize, as confirmed by X-ray diffraction and Raman spectroscopy. X-ray photoelectron spectroscopy and x-ray reflectivity show a stable 3.5 nm surface oxide layer, indicating a self-arresting oxidative process. Although the oxide layer does impact resistivity measurements, the electrical response remains dominated by SnSe post-exposure. This work shows that SnSe films can be used in ambient conditions with minimal risk of long-term degradation, which is critical for the development of piezoelectric or photovoltaic devices
Publication: Jonathan Chin et al., MRS Comm. (2024).
Instrument 10.60551/gqq8-yj90; Data 10.26207/epv5-2y55
2DCC Role:This research resulted from a user project and an RSVP experience. Samples were grown in the 2DCC thin films MBE facility.