Ultrasensitive photodetectors based on monolayer MoS2

Two-dimensional materials are an emerging class of new materials with a wide range of electrical properties and potential practical applications. Although graphene1 is the most well-studied two-dimensional material, single layers of other materials, such as insulating BN (ref. 2) and semiconducting MoS2 (refs 3, 4) or WSe2 (refs 5, 6), are gaining increasing attention as promising gate insulators and channel materials for field-effect transistors. Because monolayer MoS2 is a direct-bandgap semiconductor7,8 due to quantum-mechanical confinement7,9,10, it could be suitable for applications in optoelectronic devices where the direct bandgap would allow a high absorption coefficient and efficient electron–hole pair generation under photoexcitation. Here, we demonstrate ultrasensitive monolayer MoS2 phototransistors with improved device mobility and ON current. Our devices show a maximum external photoresponsivity of 880 A W−1 at a wavelength of 561 nm and a photoresponse in the 400–680 nm range. With recent developments in large-scale production techniques such as liquid-scale exfoliation11,12,13 and chemical vapour deposition-like growth14,15, MoS2 shows important potential for applications in MoS2-based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy. A very sensitive photodector based on molybdenum disulphide with potential for integrated optoelectronic circuits, light sensing, biomedical imaging, video recording or spectroscopy is now demonstrated.