Polymorphic one-dimensional (N2H4)2ZnTe: Soluble precursors for the formation of hexagonal or cubic zinc telluride
Abstract
Two hydrazine zinc(II) telluride polymorphs, (N2H 4)2ZnTe, have been isolated, using ambient-temperature solution-based techniques, and the crystal structures determined: α-(N2H4)2ZnTe (1) [P21, a = 7.2157(4) Å, b = 11.5439(6) Å, c = 7.3909(4) Å, β = 101.296(1)°, Z = 4] and β-(N2H4)2ZnTe (2) [Pn, a = 8.1301(5) Å, b = 6.9580(5) Å, c = 10.7380(7) Å, β = 91.703(1)°, Z = 4]. The zinc atoms in 1 and 2 are tetrahedrally bonded to two terminal hydrazine molecules and two bridging tellurium atoms, leading to the formation of extended one-dimensional (1-D) zinc telluride chains, with different chain conformations and packings distinguishing the two polymorphs. Thermal decomposition of (N2H4) 2ZnTe first yields crystalline wurtzite (hexagonal) ZnTe at temperatures as low as 200°C, followed by the more stable zinc blende (cubic) form at temperatures above 350°C. The 1-D polymorphs are soluble in hydrazine and can be used as convenient precursors for the low-temperature solution processing of p-type ZnTe semiconducting films. © 2005 American Chemical Society.