Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA.
Nanotechnology. 2012 Sep 28;23(38):385203. doi: 10.1088/0957-4484/23/38/385203. Epub 2012 Sep 4.
Gate dependent photoconductivity of carbon nanotube (CNT) field effect phototransistors (FEPs) was systematically investigated in this study. The photo-response comparisons of CNT FEPs with symmetric and asymmetric metal structures connecting to the same CNT revealed that the gate effect contributed to a sensitivity improvement with a lower dark current, a higher photocurrent, and an enhanced photovoltage. A functionalized asymmetric FEP, fabricated by partially doping the CNT utilizing a polyethylene imine (PEI) polymer, verified that FEPs delivered a better performance by using asymmetric structures. A multi-gate FEP, with three pairs of side-gates that can electrostatically dope different sections of a CNT independently, was fabricated to examine the gate structure dependent photo-responses. Experimental measurements showed an unconventional photocurrent improvement that was weakly dependent on the gate location, which was attributed to the unique charge distribution of one-dimensional semiconductors.
本研究系统地研究了碳纳米管（CNT）场效应光电晶体管（FEPs）的栅极依赖光电导。通过比较具有对称和非对称金属结构的 CNT FEPs 的光响应，发现栅极效应有助于提高灵敏度，同时降低暗电流、提高光电流并增强光电压。通过使用聚乙烯亚胺（PEI）聚合物部分掺杂 CNT 制备的功能化非对称 FEP 验证了使用非对称结构可以使 FEPs 获得更好的性能。制造了一个具有三对侧栅的多栅 FEP，这些侧栅可以独立地静电掺杂 CNT 的不同部分，以研究栅极结构对光响应的影响。实验测量结果表明，光电流的非常规改善与栅极位置弱相关，这归因于一维半导体的独特电荷分布。
