Composition and Face Polarity Influences on Mechanical Properties of (111) Cd1-yZnyTe Determined by Indentation

(111)-oriented CdZnTe semiconductor material exhibits a crystal polarity and hence, a face terminated by Cd atoms, conventionally called (111) A face with an opposite face terminated by Te atoms, called (111) B face. These A and B faces have different properties. Their mechanical properties have been studied by mechanical indentation. Sample surfaces were carefully prepared and mechanically and chemically polished, while the crystalline orientation and material defectivity was monitored on both faces using x-ray rocking curve measurements around the (222) orientation in order to evaluate faces with similar quality. The elastic moduli and hardness values of the A and B faces of CdZnTe were similar. Hardness increased from 0.60 GPa to 0.90 GPa with Zn concentration on the B face as a result of solution strengthening. Crack formation and propagation was carefully studied. Both toughness value and crack resistance were affected by polarity. A model involving plastic dislocation flow is proposed to interpret the results.