Song Jungeun, Kwon Soyeong, Jeong Hyunjeong, Choi Hyeji, Nguyen Anh Thi, Park Ha Kyung, Park Hyeong-Ho, Jo William, Lee Sang Wook, Kim Dong-Wook
Department of Physics, Ewha Womans University, Seoul 03760, Korea.
Nanodevice Laboratory, Korea Advanced Nano Fab Center, Suwon 16229, Korea.
Nanomaterials (Basel). 2022 May 5;12(9):1567. doi: 10.3390/nano12091567.
We fabricated hybrid nanostructures consisting of MoS monolayers and Au nanopillar (Au-NP) arrays. The surface morphology and Raman spectra showed that the MoS flakes transferred onto the Au-NPs were very flat and nonstrained. The Raman and photoluminescence intensities of MoS/Au-NP were 3- and 20-fold larger than those of MoS flakes on a flat Au thin film, respectively. The finite-difference time-domain calculations showed that the Au-NPs significantly concentrated the incident light near their surfaces, leading to broadband absorption enhancement in the MoS flakes. Compared with a flat Au thin film, the Au-NPs enabled a 6-fold increase in the absorption in the MoS monolayer at a wavelength of 615 nm. The contact potential difference mapping showed that the electric potential at the MoS/Au contact region was higher than that of the suspended MoS region by 85 mV. Such potential modulation enabled the Au-NPs to efficiently collect photogenerated electrons from the MoS flakes, as revealed by the uniform positive surface photovoltage signals throughout the MoS surface.
我们制备了由二硫化钼（MoS）单层和金纳米柱（Au-NP）阵列组成的混合纳米结构。表面形貌和拉曼光谱表明，转移到金纳米颗粒上的MoS薄片非常平整且无应变。MoS/Au-NP的拉曼强度和光致发光强度分别比平坦金薄膜上的MoS薄片大3倍和20倍。时域有限差分计算表明，金纳米颗粒在其表面附近显著聚集入射光，导致MoS薄片的宽带吸收增强。与平坦的金薄膜相比，金纳米颗粒在615nm波长处使MoS单层的吸收增加了6倍。接触电势差映射表明，MoS/Au接触区域的电势比悬浮MoS区域的电势高85mV。如整个MoS表面均匀的正表面光电压信号所示，这种电势调制使金纳米颗粒能够有效地从MoS薄片收集光生电子。
