Young's modulus of thin SmS films measured by nanoindentation and laser acoustic wave

[摘要] High quality phase pure samarium sulphide (SmS) thin films with low surface roughness were prepared by electron beam evaporation using a samarium metal source in an H2S atmosphere. SmS shows a strong piezoresistive response due to a phase transition between a semiconducting and metallic state, which can be employed in piezo-electronic devices and stress sensing. Measurement of fundamental mechanical properties such as Young's modulus is thus a major objective to assess the elastic behaviour of SmS under external stress. Nano-indentation was used to measure the elastic modulus of thin semiconducting films with nominal thickness of 100 nm, 200 nm and 400 nm on silicon substrate at different loads. The indentation results were fitted to a modified King's model to exclude the effect of the substrate, giving Young's moduli of the films in the range of 79-82 GPa, consistent with measurements with a Laser Surface Acoustic Wave system (LAwave) and results from literature.

[发布日期] 2021-09-15

[关键词] Samarium sulphide;Thin film;Nanoindentation;LAwave;Young's modulus