Synthesis of single-phase layered oxychalcogenide La2CdO2Se2:: crystal structure, optical and electrical properties

A single-phase La2CdO2Se2 powder was successfully synthesized and its optical and electrical properties were examined. Single-phase La2CdO2Se2 was obtained by preserving the stoichiometric composition of the initial ingredients, especially Cd and Se, during the sintering process. Exhibiting a yellowish white color, the synthesized sample has a large optical bandgap of similar to3.3 eV. The crystal structure, refined by a Rietveld method taking into account the site occupancies and isotropic thermal vibration parameters of Cd and Se, indicates that La2CdO2Se2 belongs to space group P4(2)/nmc. Instability against Cd or Se vacancy formation makes it difficult to generate carriers through vacancies or allo-valent ions doping, leading to electrical insulating properties both in as-prepared and intentionally doped La2CdO2Se2 form.