The Young Modulus and Microhardness Anisotropy in (Pb,Cd)Te Solid Solution Crystallizing in the Rock Salt Structure and Containing 5% of Cd

Abstract

A single crystal of (Pb,Cd)Te solid solution with Cd content equal to 5% was grown by self-selecting vapour growth technique and characterized by powder X-ray diffraction using the X'Pert PANalytical diffractometer and Cu Kα 1 radiation. The X-ray diffraction pattern refinement demonstrated the fcc structure of the rock-salt type of investigated sample, no precipitates or other crystal phases were detected. The sample chemical composition was determined on the basis of measured lattice parameter value. Next, the Young modulus and microhardness were determined by the nanoindentation for carefully prepared, (001), (011) and (111)-oriented single crystal plates. The slight anisotropy of two parameters mentioned above has been found and compared with available literature data.

Anisotropy of Young's Modulus and Microhardness of PbTe

“…The experimental curves corresponding to the nanoindentation depth dependence on the applied load, de- This finding is in a qualitative agreement with the theoretical predictions given in [18] and confirms our previous results taken for (Pb,Cd)Te solid solution single crystal containing 5% of CdTe [17]. The comparison of the values of E and H determined in PbTe as a result of present studies and those corresponding to (Pb,Cd)Te solid solution, taken from [17], is shown in Fig. 2.…”

“…The suggested hardness anisotropy seems to be anomalously high in comparison to other sixfold coordinated compounds, listed in [18]. The anisotropy of both hardness and Young's modulus were directly determined for (Pb,Cd)Te solid solution only using a single crystal containing about 5% of CdTe [17]. The measured anisotropy does not exceed 10% which is in a clear contradiction to theoretical prediction mentioned above.…”

“…One can improve the mechanical properties of a given semiconductor by the crystal doping or alloying with another compound. Several further reports were devoted to the mechanical properties of solid solutions grown on the basis of PbTe, like, e.g., (Pb,Ge)Te or (Pb,Cd)Te (see [13][14][15][16][17] and references therein). However, such basic experimental data as anisotropy of Young's modulus (E) and that of the hardness (H) are not available for such "classical" material as PbTe.…”

“…Under these circumstances the question arises: is the theoretical anisotropy for the IV-VI semiconductor overestimated or a relatively low anisotropy observed in the (Pb,Cd)Te solid solution results from PbTe doping with Cd? The last possibility is not excluded because the CdTe solubility in PbTe is very low (about 1%) and the solid solution single crystal employed in the measurements reported in [17] was grown by a particular technique, and has a metastable character.…”

Low-Temperature Neutron Diffraction in the (Pb,Cd)Te Solid Solution Containing 2.2% of Cd

“…A PbTe alloying with other binary telluride is a wellknown method to improve selected properties of a crystal (like, e.g., to modify such mechanical property as a hardness, the parameter important for various applications). Apart from the (Pb,Ge)Te solid solution a few other materials grown on the basis of PbTe are known and intensively investigated, among them the (Pb,Cd)Te system (see, e.g., [6][7][8][9][10][11] and references). Due to a low CdTe solubility limit in the PbTe (about 1% under the thermal equilibrium conditions at room temperature) this solid solution can be considered as a metastable crystal for a higher CdTe content.…”