Direct electrodeposition of highly dense 50 nm Bi₂Te _3-ySe_y nanowire arrays

Films and arrays of 200 and 50 nm diameter wires of Bi₂Te ₃-_xSe_x have been electrodeposited in the following general reaction: 2Bi³⁺ + (3-y)HTeO₂ ⁺ + (y)H₂SeO₃ + (9+y)H⁺ + 18e ^- → Bi₂Te_3-ySe_y + (6+y)H ₂O. Films produced from an electrolyte of 0.0075 M Bi, 0.0090 M Te, and 0.0010 M Se in 1 M HNO₃ at a potential of ∼0 V vs Ag/AgCl are single phase with composition Bi₂Te_2.6Se _0.4 as determined by X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Similar conditions yield arrays of 200 and 50 nm Bi₂Te_3-ySe_y wires when deposited into porous alumina templates. The wires are single phase, crystalline, and textured, with up to 85% pore filling.