Her Yung-Chiun, Yeh Bu-Yu, Huang Sing-Lin
Department of Materials Science and Engineering, National Chung Hsing University , Taichung 40227, Taiwan.
ACS Appl Mater Interfaces. 2014 Jun 25;6(12):9150-9. doi: 10.1021/am5012518. Epub 2014 Jun 3.
We have synthesized brushlike p-Te/n-SnO2 hierarchical heterostructures by a two-step thermal vapor transport process. The morphologies of the branched Te nanostructures can be manipulated by adjusting the source temperature or the argon flow rate. The growth of the branched Te nanotubes on the SnO2 nanowire backbones can be ascribed to the vapor-solid (VS) growth mechanism, in which the inherent anisotropic nature of Te lattice and/or dislocations lying along the Te nanotubes axis should play critical roles. When exposed to CO and NO2 gases at room temperature, Te/SnO2 hierarchical heterostructures changed the resistance in the same trend and exhibited much higher responses and faster response speeds than the Te nanotube counterparts. The enhancement in gas sensing performance can be ascribed to the higher specific surface areas and formations of numerous Te/Te or TeO2/TeO2 bridging point contacts and additional p-Te/n-SnO2 heterojunctions.
我们通过两步热蒸发传输过程合成了刷状p-Te/n-SnO₂分级异质结构。通过调节源温度或氩气流速，可以控制分支状碲纳米结构的形貌。分支状碲纳米管在SnO₂纳米线骨架上的生长可归因于气固（VS）生长机制，其中碲晶格固有的各向异性性质和/或沿碲纳米管轴的位错应起关键作用。当在室温下暴露于CO和NO₂气体时，Te/SnO₂分级异质结构的电阻以相同趋势变化，并且与碲纳米管对应物相比表现出更高的响应和更快的响应速度。气敏性能的增强可归因于更高的比表面积以及大量Te/Te或TeO₂/TeO₂桥接点接触和额外的p-Te/n-SnO₂异质结的形成。
