Probing 2D black phosphorus by quantum capacitance measurements

Kuiri, Manabendra and Kumar, Chandan and Chakraborty, Biswanath and Gupta, Satyendra N and Naik, Mit H and Jain, Manish and Sood, AK and Das, Anindya (2015) Probing 2D black phosphorus by quantum capacitance measurements. In: NANOTECHNOLOGY, 26 (48).

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Abstract

Two-dimensional materials and their heterostructures have emerged as a new class of materials, not only for fundamental physics but also for electronic and optoelectronic applications. Black phosphorus (BP) is a relatively new addition to this class of materials. Its strong in-plane anisotropy makes BP a unique material for making conceptually new types of electronic devices. However, the global density of states (DOS) of BP in device geometry has not been measured experimentally. Here, we report the quantum capacitance measurements together with the conductance measurements on an hBN-protected few-layer BP (similar to six layers) in a dual-gated field effect transistor (FET) geometry. The measured DOS from our quantum capacitance is compared with density functional theory (DFT). Our results reveal that the transport gap for quantum capacitance is smaller than that in conductance measurements due to the presence of localized states near the band edge. The presence of localized states is confirmed by the variable range hopping seen in our temperature dependence conductivity. A large asymmetry is observed between the electron and hole side. This asymmetric nature is attributed to the anisotropic band dispersion of BP. Our measurements establish the uniqueness of quantum capacitance in probing the localized states near the band edge, hitherto not seen in conductance measurements.

Item Type:	Journal Article
Publication:	NANOTECHNOLOGY
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	black phosphorus; quantum capacitance; localized states; density of states; anisotropy; heterostructure; hBN
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	14 Jan 2016 06:46
Last Modified:	14 Jan 2016 06:46
URI:	http://eprints.iisc.ac.in/id/eprint/53087

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