State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871, P. R. China.
Nanoscale. 2017 Nov 30;9(46):18175-18179. doi: 10.1039/c7nr05706g.
The construction of the mixed-dimensional van der Waals (vdW) heterostructures with two-dimensional (2D) and one-dimensional (1D) materials can advantageously integrate their respective dimensional properties to produce new device functionalities and/or enhance device performance. In this case, a single semiconductor nanowire (NW) can function as an optical cavity and a gain medium, while the atomically thin 2D material does not strongly absorb the NW's light emission or disturb the optical propagation mode. Therefore, the mixed-dimensional 2D/1D vdW heterostructure might provide a new route to realize high-efficiency light-emitting diodes (LEDs) and/or even electrically driven lasers. Here, we report a LED based on a p-type MoS nanosheet and an n-type CdSe NW. The 2D/1D vdW heterojunction diode exhibits a rectification ratio of ∼24 at V = ±3 V, and a low turn-on voltage of ∼1.5 V. Under the forward bias exceeding the turn-on voltage, the 2D/1D vdW heterojunction exhibits strong electroluminescence centered at ∼709 nm, corresponding to the band-edge emission of the CdSe NW. This novel 2D/1D vdW device, which takes advantages of both 2D and 1D semiconductors, enables potential future applications in electrically driven lasers, high-sensitivity sensors, and transparent flexible devices.
构建二维（2D）和一维（1D）材料的混合维度范德华（vdW）异质结构可以有利地整合它们各自的维度特性，从而产生新的器件功能和/或增强器件性能。在这种情况下，单个半导体纳米线（NW）可以充当光学腔和增益介质，而原子薄的 2D 材料不会强烈吸收 NW 的光发射或干扰光学传播模式。因此，混合维度 2D/1D vdW 异质结构可能为实现高效发光二极管（LED）甚至电驱动激光器提供新途径。在这里，我们报告了一种基于 p 型 MoS 纳米片和 n 型 CdSe NW 的 LED。2D/1D vdW 异质结二极管在 V = ±3 V 时的整流比约为 24，开启电压约为 1.5 V。在超过开启电压的正向偏置下，2D/1D vdW 异质结表现出强烈的电致发光，中心波长约为 709nm，对应于 CdSe NW 的带边发射。这种新型 2D/1D vdW 器件结合了 2D 和 1D 半导体的优势，有望在电驱动激光器、高灵敏度传感器和透明柔性器件等领域得到应用。
