A study of optoelectronic properties of carbon nanomaterials: transistors, sensors, and beyond
The aims of this dissertation are to develop synthesis techniques for carbon nanomaterials, to investigate their electrical and optical properties, and to explore their applications in energy conversion and biological systems.By combining the techniques of material synthesis and device fabrication and characterization, two primary carbon nanomaterials, carbon nanotubes (CNTs) and graphene, have been systematically studied. Two different strategies have been developed to control the growth morphology and density of CNTs by chemical vapor deposition. Suspended CNT transistors have also been fabricated to explore the local electrostatic changes in a liquid environment through scanning photocurrent measurements. Moreover, we have employed a facile method to enhance the photocurrent response of graphene, another important carbon nanomaterial, by altering the graphene morphology. Gate-dependent scanning photocurrent measurements indicate that the photothermoelectric effect plays a key role in the photocurrent enhancement of graphene.