Facial synthesis of KCu7S4 nanobelts for nonvolatile memory device applications

Abstract

Tetragonal KCu₇S₄ nanobelts (NBs) with width of 200–600 nm and length of up to hundreds of micrometers were facially synthesized via a solution-based method. Electrical analysis reveals that the as-fabricated NB exhibits typical p-type semiconducting characteristics with an exceptionally high carrier mobility of ∼870 cm² V⁻¹ s⁻¹, which may be attributed to the quasi-1D conduction path along the c axis in the structure of KCu₇S₄. A further study of a device based on the Cu/KCu₇S₄ NB/Au Schottky junction shows a stable memory behavior with a set voltage of about 0.6 V, a current ON/OFF ratio of about 10⁴, and a retention time >10⁴ s. Such resistive switching characteristics, according to our analysis are due to the interfacial oxide layers that can efficiently trap the electrons by the oxygen vacancies. This study will offer opportunities for the development of high-performance memory devices with new geometries.