Preparation and properties of two indium antimony selenides

Crystals of antimony-doped In₂Se₃ were grown by the Bridgeman method. This compound, whose composition is In_1.8Sb_0.2Se₃, appears to be isostructural with In_1.9As_0.1Se₃. The refined unit cell parameters are a = 3.97(1), c = 18.87(1) Å. Orthorhombic crystals of InSbSe₃ were grown from an isothermal melt. The refined unit cell parameters are a = 9.43(1), b = 14.02(5), and c = 3.96(1) Å. These parameters agree with those determined for α-InSbSe₃ by other studies. The observed densities measured by a hydrostatic technique are 5.98(3) g/cm³ for In_1.8Sb_0.2Se₃ and 6.07(2) g/cm³ for InSbSe₃. The room temperature dc resistivity for In_1.8Sb_0.2Se₃ has been found to be 4.4 × 10⁴ Ω-cm, whereas that of InSbSe₃ has been found to be 15.2(1) Ω-cm. A resistivity versus temperature study has beenn carried out for InSbSe₃ between 230 and 400°K. Optical studies indicate that In_1.8Sb_0.2Se₃ is an n-type semiconductor with a band gap of 1.1 eV and InSbSe₃ is a p-type semiconductor with a band gap of 0.92 eV.