Micromechanical properties of the long-term aged gap single crystals

The goal of this work is investigation of the long-term evolution of hardness and plasticity of the GaP single crystals, doped by various types and concentrations of impurities. The measurements of microhardness of the doped GaP single crystals aged over 40 years are shown. The dopants are distributed into the groups: 1) the isoelectronic impurities substituting P or Ga in GaP crystal lattice sites (respectively N, Bi and B); 2) La, Sm and Gd lanthanides situated in GaP lattice interstitials; 3) the elements of the Fe group and 4) acceptor Zn and donor Te, substituting Ga and P respectively. (authors)