n-Type KCu3S2 microbelts: optical, electrical, and optoelectronic properties
KCu3S2 microbelts with lengths up to 80 μm and widths of 200–800 nm have been synthesized using a composite-hydroxide mediated (CHM) approach and their optical, electrical and optoelectronic properties were systematically characterized for the first time. As-synthesized KCu3S2 microbelts were characterized to be semiconductors with a bandgap of 1.64 eV by UV-vis absorption spectroscopy and room-temperature PL spectroscopy. Ultraviolet photoelectron spectroscopy (UPS) and the electrical transport properties of the bottom-gate field-effect transistor (FET) revealed the n-type conduction of the KCu3S2 microbelts with a conductivity as high as ∼1.85 × 103 S cm−1. A KCu3S2/Au Schottky diode was fabricated, which showed a turn-on voltage of ∼0.3 V, a rectification ratio of ∼102 to 103, and an ideality factor of 2.1. The diode possessed a photoresponse ratio Ilight/Idark ∼ 50 and a rapid response time less than 0.5 s. The systematical electrical characterization of KCu3S2 microbelts sheds light on the potential application of KCu3S2 as a photovoltaic or optoelectronic material.