Allain, AdrienKang, JiahaoBanerjee, KaustavKis, Andras2015-11-202015-11-202015-11-20201510.1038/nmat4452https://infoscience.epfl.ch/handle/20.500.14299/120729The performance of electronic and optoelectronic devices based on two-dimensional layered crystals, including graphene, semiconductors of the transition metal dichalcogenide family such as molybdenum disulphide (MoS2) and tungsten diselenide (WSe2), as well as other emerging two-dimensional semiconductors such as atomically thin black phosphorus, is significantly affected by the electrical contacts that connect these materials with external circuitry. Here, we present a comprehensive treatment of the physics of such interfaces at the contact region and discuss recent progress towards realizing optimal contacts for two-dimensional materials. We also discuss the requirements that must be fulfilled to realize efficient spin injection in transition metal dichalcogenides. © 2015 Macmillan Publishers Limited. All rights reserved.text::journal::journal article::review article