| 초록 |
Recently, atomically thin two-dimensional materials, such as transition metal dichalcogenides (TMDs), especially molybdenum disulfide (MoS2), have attracted considerable interest for future electronic and optoelectronic applications, such as transistors, logic circuits, solar cells, photodetectors, and sensors. Intrinsic MoS2 is a n-type semiconducting material with an indirect bandgap of ~1.3 eV in bulk and a direct bandgap of 1.9 eV for a monolayer. In particular, MoS2 has a great potential for the applications in photodetection due to the excellent sensitivity of light, the formation of large area film, extreme flexibility, and high transparency. For the applications in photodetection, the use of heterojunction devices can be an effective way of manipulating the electronic and optoelectronic properties of semiconductor devices based two-dimensional nanomaterials. In this work, we demonstrate comparative studies of electrical and photoresponse properties in heterojunction devices based on a n-type MoS2/p-type Si structure. We investigated three different types of heterojunction devices: (1) metal/Si junction devices without a MoS2 layer, (2) metal/as-grown MoS2/Si junction devices in which a MoS2 layer was directly grown on a Si substrate, (3) metal/transferred MoS2/Si junction devices in which a MoS2 layer was transferred onto a Si substrate. We show the current–voltage (I-V) characteristics of heterojunction devices under dark and illumination. We also present temperature- and light intensity-dependent photoresponse properties. |
