Hierarchical growth of CdSe dendritic nanostructures for enhanced field emission application

In this work, a facile hydrothermal route has been presented for the hierarchical growth of CdSe dendritic nanostructures by varying reducing agent (hydrazine hydrate) volume % in the presence of EDTA as a complexing agent. The morphological transition from spherical to dendritic form has demonstrated remarkable improvement in the field emission performance of CdSe. The X-ray diffraction analysis indicates the formation of highly crystalline CdSe nanostructures with average crystallite size of about 13–18 nm which is well supported by Raman spectroscopy. Further, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy analyses confirm the elemental composition of optimized material. The morphology of synthesized materials is confirmed by field emission scanning electron microscopy and transmission electron microscopy techniques. The optical analysis with UV–Vis spectroscopy (DRS mode) shows the band gap variation in the range of 1.68–1.71 eV and photoluminescence emission spectra display high-intensity band-edge emissions peak centred at 678 nm. Field emission studies indicate that the value of turn-on field for CdSe nanostructures is lowered from 5.4 to 3.75 V/µm (at 1 µA/cm²) with a reduction in threshold field value from 6.9 to 5.5 V/µm (at 10 µA/cm²) as an effect of morphological variation. The maximum current density shows a considerable rise to 92 µA/cm² (at applied field 8.2 V/µm) from the initial value of 28 µA/cm² (at 7.9 V/µm). Further, the promising field enhancement factor of 4016 is observed for CdSe dendritic nanostructures. Investigations presented herein clearly show the potential of synthesized material for field emission-based vacuum micro-electronic applications.