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Transport properties of pristine few-layer black phosphorus by van der Waals passivation in an inert atmosphere

2015; Nature Portfolio; Volume: 6; Issue: 1 Linguagem: Inglês

10.1038/ncomms7647

2041-1723

Rostislav A. Doganov, Eoin O’Farrell, Steven P. Koenig, Yuting Yeo, Angelo Ziletti, Alexandra Carvalho, David Campbell, D. F. Coker, Kenji Watanabe, Takashi Taniguchi, A. H. Castro Neto, Barbaros Özyilmaz,

MXene and MAX Phase Materials

Ultrathin black phosphorus, or phosphorene, is the second known elementary two-dimensional material that can be exfoliated from a bulk van der Waals crystal. Unlike graphene it is a semiconductor with a sizeable band gap and its excellent electronic properties make it attractive for applications in transistor, logic, and optoelectronic devices. However, it is also the first widely investigated two dimensional electronic material to undergo degradation upon exposure to ambient air. Therefore a passivation method is required to study the intrinsic material properties, understand how oxidation affects the physical transport properties and to enable future application of phosphorene. Here we demonstrate that atomically thin graphene and hexagonal boron nitride crystals can be used for passivation of ultrathin black phosphorus. We report that few-layer pristine black phosphorus channels passivated in an inert gas environment, without any prior exposure to air, exhibit greatly improved n-type charge transport resulting in symmetric electron and hole trans-conductance characteristics. We attribute these results to the formation of oxygen acceptor states in air-exposed samples which drastically perturb the band structure in comparison to the pristine passivated black phosphorus.