The crystal and electronic band structure of the diamond-like semiconductor Ag_2ZnSiS_4

摘要

Single crystals of the new diamond-like semiconductor Ag_2ZnSiS_4 have been synthesized using high-temperature, solid state synthesis at 800 °C. The compound crystallizes in the monoclinic, non-centrosymmetric space group Pn with o = 6.4052(1)A, b = 6.5484(1) A, c=7.9340(l)A,β = 90.455(1)° and R1 (for all data) = 2.42%. The electronic band structure and density of states were calculated using density functional theory (DFT) and the full potential linearized augmented plane wave (LAPW) method within the Wien2k program suite. The calculated band structure suggests that Ag_2ZnSiS_4 is a direct band gap semiconductor with a calculated band gap of 1.88 eV at the T-point. The calculated density of states of Ag_2ZnSiS_4 is compared with that of AgGaS_2. The band gap of Ag_2ZnSiS_4 was also determined experimentally as 3.28 eV via optical diffuse reflectance spectroscopy.