Field Emission from Decorated Carbon Nanotube–QDs Microstructures with a View to the Dominant Electron Paths

We present a study on the field emission properties of a hybrid system comprised of carbon nanotube (CNT) micropillars decorated with quantum dots (QDs). With controlled decoration of QDs on the CNT micropillars through a simple assisted self-assembly process, further enhancement in the field emitting property of the hybrid microstructures was detected. Upon irradiation of the hybrid structure with a broad visible-light laser beam, additional enhanced field emission was observed. Analyses using fluorescence and confocal microscopy, as well as ultraviolet photoelectron spectroscopy, suggested that electron transfer from QDs to the CNT strands and the reduced work function of the hybrid system as the contributing factors behind the enhanced field emissions. In addition, we discovered that the field emission process gave rise to lost of the QDs’ fluorescence luminosity on the microstructures in specific patterns attributable to transfers of charge carrier from QDs to the CNTs. This observation provided a new means to understand and to determine the predominant 3D path of the emission of electrons from the sample down to a micrometer scale level