Formation mechanism and antisite defects of scalable room-temperature aqueous synthesis of SnSe: Effects of the pH value on the reaction yield, mean crystallite size, chemical composition, and carrier concentration

Abstract

A simple and scalable wet chemical method was adopted to synthesize a series of single-phase nanosized SnSe at room temperature with the solution controlled at various pH values. The lattice constants, chemical compositions, carrier concentration, bond length of bonded atoms, reaction yield, and antisite defects of resulting materials exhibit significant dependence on the pH values of the aqueous solution in the synthesis. Detailed studies on the formation mechanism of SnSe indicate that our approach involves the reaction between elemental Sn and Se, instead of the competitive precipitating reaction between Sn2+ and Se2−. The energetic elemental Se might be provided by polyselenide ions Sex2−. The reaction yield increases after treating SnSe with hydrochloric acid. According to both elemental analyses using electron probe microanalyzer and studies of extended x-ray absorption fine structure spectra, the Se vacancy is generated and is accompanied by formation of antisite defects by treating SnSe with hydrochloric acid.