arXiv subjects

Pulickel M. Ajayan

Publications and source records attributed to Pulickel M. Ajayan.

56 records · Page 4Linked to original sources

arXiv2011

Anomalous insulator metal transition in boron nitride-graphene hybrid atomic layers

The study of two-dimensional (2D) electronic systems is of great fundamental significance in physics. Atomic layers containing hybridized domains of graphene and hexagonal boron nitride (h-BNC) constitute a new kind of disordered 2D electronic system. Magneto-electric transport measurements performed at low temperature in vapor phase synthesized h-BNC atomic layers show a clear and anomalous transition from an insulating to a metallic behavior upon cooling. The observed insulator to metal transition can be modulated by electron and hole doping and by the application of an external magnetic field. These results supported by ab-initio calculations suggest that this transition in h-BNC has distinctly different characteristics when compared to other 2D electron systems and is the result of the coexistence between two distinct mechanisms, namely, percolation through metallic graphene networks and hopping conduction between edge states on randomly distributed insulating h-BN domains.

cond-mat.mes-hall↗

arXiv2011

Large Area Vapor Phase Growth and Characterization of MoS2 Atomic Layers on SiO2 Substrate

Monolayer Molybdenum disulfide (MoS2), a two-dimensional crystal with a direct bandgap, is a promising candidate for 2D nanoelectronic devices complementing graphene. There have been recent attempts to produce MoS2 layers via chemical and mechanical exfoliation of bulk material. Here we demonstrate the large area growth of MoS2 atomic layers on SiO2 substrates by a scalable chemical vapor deposition (CVD) method. The as-prepared samples can either be readily utilized for further device fabrication or be easily released from SiO2 and transferred to arbitrary substrates. High resolution transmission electron microscopy and Raman spectroscopy on the as grown films of MoS2 indicate that the number of layers range from single layer to a few layers. Our results on the direct growth of MoS2 layers on dielectric leading to facile device fabrication possibilities show the expanding set of useful 2D atomic layers, on the heels of graphene, which can be controllably synthesized and manipulated for many applications.

cond-mat.mtrl-sci↗