Black phosphorus (bP) is the second known elemental allotrope with a layered crystal structure that can be mechanically exfoliated down to atomic layer thickness. We have fabricated bP naked quantum wells in a back-gated field effect transistor geometry with bP thicknesses ranging from 6±1 nm to 47±1 nm. Using an encapsulating polymer superstrate, we have suppressed bP oxidation and have observed field effect mobilities up to 600 cm2/Vs and on/off current ratios exceeding 105. Importantly, Shubnikov-de Haas (SdH) oscillations observed in magnetotransport measurements up to 35 T reveal the presence of a 2-D hole gas with Schr\"odinger fermion character in an accumulation layer at the bP/oxide interface. Our work demonstrates that 2-D electronic structure and 2-D atomic structure are independent. 2-D carrier confinement can be achieved in layered semiconducting materials without necessarily approaching atomic layer thickness, advantageous for materials that become increasingly reactive in the few-layer limit such as bP.
@article{arxiv.1412.0259,
title = {Two-Dimensional Magnetotransport in a Black Phosphorus Naked Quantum Well},
author = {V. Tayari and N. Hemsworth and I. Fakih and A. Favron and E. Gaufrès and G. Gervais and R. Martel and T. Szkopek},
journal= {arXiv preprint arXiv:1412.0259},
year = {2015}
}