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High‐Density Sb 2 Te 3 Nanopillars Arrays by Templated, Bottom‐Up MOCVD Growth
Author(s) -
Cecchini Raimondo,
Gajjela Raja S. R.,
Martella Christian,
Wiemer Claudia,
Lamperti Alessio,
Nasi Lucia,
Lazzarini Laura,
Nobili Luca G.,
Longo Massimo
Publication year - 2019
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201901743
Subject(s) - metalorganic vapour phase epitaxy , nanopillar , materials science , nanotechnology , nanostructure , optoelectronics , epitaxy , layer (electronics)
Abstract Sb 2 Te 3 exhibits several technologically relevant properties, such as high thermoelectric efficiency, topological insulator character, and phase change memory behavior. Improved performances are observed and novel effects are predicted for this and other chalcogenide alloys when synthetized in the form of high‐aspect‐ratio nanostructures. The ability to grow chalcogenide nanowires and nanopillars (NPs) with high crystal quality in a controlled fashion, in terms of their size and position, can boost the realization of novel thermoelectric, spintronic, and memory devices. Here, it is shown that highly dense arrays of ultrascaled Sb 2 Te 3 NPs can be grown by metal organic chemical vapor deposition (MOCVD) on patterned substrates. In particular, crystalline Sb 2 Te 3 NPs with a diameter of 20 nm and a height of 200 nm are obtained in Au‐functionalized, anodized aluminum oxide (AAO) templates with a pore density of ≈5 × 10 10 cm −2 . Also, MOCVD growth of Sb 2 Te 3 can be followed either by mechanical polishing and chemical etching to produce Sb 2 Te 3 NPs arrays with planar surfaces or by chemical dissolution of the AAO templates to obtain freestanding Sb 2 Te 3 NPs forests. The illustrated growth method can be further scaled to smaller pore sizes and employed for other MOCVD‐grown chalcogenide alloys and patterned substrates.