Formation of Graphene–Silicon Junction by Room Temperature Reduction With Simultaneous Defects Removal

A novel method of preparing reduced graphene oxide (rGO)–silicon (Si) junctions free from native silicon oxide layer at room temperature is reported. The method is based on a simultaneous reduction–dissolution reaction between graphene oxide (GO) and fresh Si atoms with the assistance of dilute hydrofluoric acid (HF). The rGO–Si junction is characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. A reaction mechanism is proposed that Si is oxidized and dissolved by HF, which transfers the electronic holes to GO and facilitates the removal of its oxygen-containing groups. The use of HF provides a unique benefit to the contact formation that native oxide on Si is removed by HF instantaneously and only fresh Si surface is in contact with rGO. Therefore, the method provides a new strategy of preparing rGO-native oxide-free Si interface, which has been a fundamental challenge in the fabrication of graphene–Si junction. Electrical tests show that rGO–Si interface has a slightly higher barrier than Al–Si.