Adhikari Bikram, Limbu Tej B, Vinodgopal Kizhanipuram, Yan Fei
Department of Chemistry and Biochemistry, North Carolina Central University, Durham, NC 27707, United States of America.
Nanotechnology. 2021 May 24;32(33). doi: 10.1088/1361-6528/abff8f.
Two-dimensional (2D) molybdenum ditelluride (MoTe) is a member of the transition-metal dichalcogenides family, which is an especially promising platform for surface-enhanced Raman scattering (SERS) applications, due to its excellent electronic properties. However, the synthesis of large-area highly crystalline 2D MoTewith controllable polymorphism is a huge challenge due to the small free energy difference (∼40 meV per unit cell) between semiconducting 2H-MoTeand semi-metallic 1 T'-MoTe. Herein, we report an optimized route for the synthesis of 2H- and 1 T'-MoTefilms by atmospheric-pressure chemical vapor deposition. The SERS study of the as-grown MoTefilms was carried out using methylene blue (MB) as a probe molecule. The Raman enhancement factor on 1 T'-MoTewas found to be three times higher than that on 2H-MoTeand the 1 T'-MoTefilm is an efficient Raman-enhancing substrate that can be used to detect MB at nanomolar concentrations. Our study also imparts knowledge on the significance of a suitable combination of laser excitation wavelength and molecule-material platform for achieving ultrasensitive SERS-based chemical detection.
二维（2D）二碲化钼（MoTe₂）是过渡金属二硫属化物家族的一员，由于其优异的电子特性，它是表面增强拉曼散射（SERS）应用中一个特别有前景的平台。然而，由于半导体2H-MoTe₂和半金属1T'-MoTe₂之间的自由能差较小（约每晶胞40毫电子伏特），合成具有可控多晶型的大面积高结晶度2D MoTe₂是一项巨大的挑战。在此，我们报道了一种通过常压化学气相沉积合成2H-和1T'-MoTe₂薄膜的优化路线。使用亚甲基蓝（MB）作为探针分子对生长的MoTe₂薄膜进行了SERS研究。发现1T'-MoTe₂上的拉曼增强因子比2H-MoTe₂上的高两倍，并且1T'-MoTe₂薄膜是一种高效的拉曼增强基底，可用于检测纳摩尔浓度下的MB。我们的研究还揭示了激光激发波长与分子-材料平台的合适组合对于实现基于SERS的超灵敏化学检测的重要性。
