Nanoindentation of HgCdTe prepared by molecular beam epitaxy

Abstract

Nanoindentation has been used to investigate the elastoplastic behavior of Hg 0.7 Cd 0.3 Te prepared by molecular beam epitaxy. It was found that Hg 0.7 Cd 0.3 Te had a modulus of elasticity of ϳ50 GPa and hardness of ϳ0.66 GPa. The HgCdTe response to nanoindentation was found to be purely elastic for low loads and developed into ϳ10% elastic and ϳ90% plastic response for higher-load indentation exhibiting significant amounts of creep. The onset of plasticity has been observed to be marked by discontinuities or "pop-in" events in the indenter load-penetration curves at sheer stresses of ϳ1.8 GPa, and has been correlated with the homogeneous nucleation and propagation of dislocations.

Mechanical and Thermal Properties

“…Available experimental data of Young's modulus for MCT, which are included in Table 8.3, originate from microindentation measurements of Kurilo et al [75] for bulk crystals (x = 0, 0.2, 1.0) and nanoindentation measurements Martyniuk et al [79,80] for MBE, LPE, as well as bulk material (x = 0.3), which are in good agreement with each other. Since the indentation tip while deforming the crystal structure induces strains locally, it produces nearly uniform strains around dislocations and the experimental Young's modulus values are in closer agreement with the Young's modulus values from Voigt rather than Reuss averaging.…”

“…In prior studies, Martyniuk et al used nanoindentation to investigate the elastoplastic behavior of Hg 0.7 Cd 0.3 Te prepared by MBE [79] and LPE, as well as of bulk Hg 0.7 Cd 0.3 Te prepared by the modified Bridgman method [80]. Similar mechanical properties where found for all samples.…”

“…Numerous data are available on Hg 1−x Cd x Te hardness at room temperature as a function of composition, x , for various growth methods: quenched ingots [85,86], travelling heater method (THM) [86][87][88], Bridgman method [80,86,[89][90][91], isothermal vapor phase epitaxy (ISOVPE) [92,93], LPE [80,92], MBE [79] or other [94,95]. Myles and Ekpenuma [98], Eqn.…”

“…The reviewed deformation characteristics mostly encompass compression [104], bending [105,106], and nanoindentation [79,80] testing of the MCT material.…”

Research progress on ultra-precision machining technologies for soft-brittle crystal materials

“…Mercury cadmium telluride (HgCdTe, MCT) single crystal is the most significant material for infrared optoelectronic devices and MCT-based high performance infrared devices, and is widely used in the fields of aeronautics and astronautics [4]. Cadmium zinc telluride (CdZnTe, CZT) single crystal is the most promising material for the fabrication of room temperature radiation detectors [5,6] and is also widely used as the perfect substrates for growing epitaxial layers of MCT crystal [7].…”