Black Phosphorus Transistors with Near Band Edge Contact Schottky Barrier

• DOI: 10.1038/srep18000
• Publication Date: 2015-12-15T10:01:56Z
• Authors: Zhi-Peng Ling; Soumya Sakar; Sinu Mathew; Jun-Tao Zhu; K. Gopinadhan; T. Venkatesan; Kah-Wee Ang
• Keywords: Black Phosphorus; Metal–semiconductor junction

Abstract Black phosphorus (BP) is a new class of 2D material which holds promise for next generation transistor applications owing to its intrinsically superior carrier mobility properties. Among other issues, achieving good ohmic contacts with low source-drain parasitic resistance in BP field-effect transistors (FET) remains challenge. For the first time, we report contact technology that employs use high work function nickel (Ni) and thermal anneal produce metal alloy effectively reduces Schottky barrier height (Φ B ) FET. When annealed at 300 °C, Ni electrode was found react underlying crystal resulted formation nickel-phosphide (Ni 2 P) alloy. This serves de-pin Fermi level close valence band edge realizes record hole Φ merely ~12 meV. The has also been shown be thickness-dependent, wherein increasing multi-layers results smaller due bandgap energy shrinkage. integration hafnium-dioxide high-k gate dielectric additionally enables significantly improved subthreshold swing (SS ~ 200 mV/dec), surpassing previously reported FETs conventional SiO > 1 V/dec).