Ko Tsung-Shine, Lin En-Ting, Ho Yen-Teng, Deng Chen-An
Department of Electronic Engineering, National Changhua University of Education, No. 2, Shi-Da Road, Changhua 50074, Taiwan.
International College of Semiconductor Technology, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Materials (Basel). 2023 Apr 12;16(8):3054. doi: 10.3390/ma16083054.
In the application of WS as a surface-enhanced Raman scattering (SERS) substrate, enhancing the charge transfer (CT) opportunity between WS and analyte is an important issue for SERS efficiency. In this study, we deposited few-layer WS (2-3 layers) on GaN and sapphire substrates with different bandgap characteristics to form heterojunctions using a chemical vapor deposition. Compared with sapphire, we found that using GaN as a substrate for WS can effectively enhance the SERS signal, with an enhancement factor of 6.45 × 10 and a limit of detection of 5 × 10 M for probe molecule Rhodamine 6G according to SERS measurement. Analysis of Raman, Raman mapping, atomic force microscopy, and SERS mechanism revealed that The SERS efficiency increased despite the lower quality of the WS films on GaN compared to those on sapphire, as a result of the increased number of transition pathways present in the interface between WS and GaN. These carrier transition pathways could increase the opportunity for CT, thus enhancing the SERS signal. The WS/GaN heterostructure proposed in this study can serve as a reference for enhancing SERS efficiency.
在将WS用作表面增强拉曼散射（SERS）基底的应用中，增加WS与分析物之间的电荷转移（CT）机会是提高SERS效率的一个重要问题。在本研究中，我们使用化学气相沉积法在具有不同带隙特性的GaN和蓝宝石基底上沉积了几层WS（2-3层）以形成异质结。与蓝宝石相比，我们发现使用GaN作为WS的基底可以有效增强SERS信号，根据SERS测量，对于探针分子罗丹明6G，增强因子为6.45×10，检测限为5×10 M。拉曼分析、拉曼映射、原子力显微镜和SERS机制表明，尽管与蓝宝石上的WS薄膜相比，GaN上的WS薄膜质量较低，但由于WS与GaN界面中存在的跃迁途径数量增加，SERS效率提高了。这些载流子跃迁途径可以增加CT的机会，从而增强SERS信号。本研究中提出的WS/GaN异质结构可为提高SERS效率提供参考。
