Synthesis and formation mechanism of helical single-crystalline CuInSe2 nanowires

Abstract

Highly ordered single-crystalline CuInSe2 nanowires array have been prepared via a facile solution approach by using anodic aluminium oxide (AAO) as a hard template. CuInSe2 nanowires with a novel helical shape are found to be formed by this approach. A screw-dislocation-induced growth process is proposed for the formation mechanism of this interesting nanostructure based on detailed structural characterizations. The CuInSe2 helical nanowires have an average diameter of 200 nm and a periodicity of about 50–100 nm. Another type of CuInSe2 nanowire with a straight shape is also found in the product and an oriented attachment mechanism has been used to explain its growth. Nanowires with both types of shapes have the same [112] growth direction. The structure, morphology, composition and optical absorption properties of the as-prepared samples were characterized using X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-Vis spectrophotometry.