Printable electronics-compatible silicon nanoparticles prepared by the facile decomposition of SiS2 and their application in a back-to-back Schottky diode

Abstract

Crystalline silicon nanoparticles (size <5 nm) are synthesized at room temperature by the decomposition of silicon sulfide (SiS₂) in a water–acid mixture followed by chemical etching. Grey free-standing silicon nanoparticles are obtained after the decomposed product is etched with a mixture of hydrofluoric acid (HF), hydrogen peroxide (H₂O₂) and ethanol. These silicon nanoparticles are not capped with any organic ligands, making them suitable for electronic applications. For the preparation of a functional Si nanoparticle dispersion, the silicon nanoparticle suspension is prepared by re-dispersing in benzonitrile or in ethanol by incorporating polypropylene glycol (PPG) as a binder. An Al/Si-nanoparticle/n⁺⁺-Si back-to-back Schottky diode is fabricated from both the Si nanoparticle suspension and the ink, and the charge transport mechanism is studied as the working temperature increases. Such versatility of these silicon nanoparticles can be ideal for any print-type deposition with a low-cost and large-area processing method.