Determination of HgCdTe elasto-plastic properties using nanoindentation

Authors: Martyniuk, M.; Sewell, R.; Musca, C.; Dell, J.; Faraone, L.

Source: Journal of Electronic Materials, Volume 35, Number 6, June 2006 , pp. 1197-1205(9)

Publisher: Springer

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Abstract:

Depth sensing indentation has been used to investigate the elasto-plastic behavior of Hg_0.7Cd_0.3Te prepared by molecular beam epitaxy, liquid phase epitaxy, as well as of bulk Hg_0.7Cd_0.3Te prepared by the modified Bridgman method. It was found that Hg_0.7Cd_0.3Te was characterized by a modulus of elasticity of E _avg ∼ 50 GPa and hardness of H _avg ∼ 0.66 GPa, independent of growth technology. The measured hardness was observed to increase with decreasing size of indentation owing to the nucleation of dislocations within the plastic zone. The elasto-plastic response of the samples to nanoindentation was observed to be purely elastic at low indentation depths and developed into ∼10% elastic and ∼90% plastic response, with an increase in penetration contact depth to above 100 nm exhibiting significant amounts of creep. The transition from purely elastic to elasto-plastic behavior has been observed to be marked by discontinuities, or “pop-in” events in the indenter load-penetration curves, with the indentation zone maximum sheer stress varying with HgCdTe growth method in the range 1.1-1.8 GPa. This onset and subsequent flow of plasticity is postulated to be associated with the spontaneous nucleation and propagation of dislocations.

Keywords: HgCdTe; nanoindentation; modulus; hardness; elasticity; viscoplasticity

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s11664-006-0241-7

Affiliations: 1: Email: mariusz@ee.uwa.edu.au

Publication date: 2006-06-01