Role of electronic structure and order of bimetal nanoparticles coating in enhanced field emission response of vertically grown CNTs

Abstract

The present study reports the synthesis of vertically aligned carbon nanotubes on a Si substrate using the thermal CVD technique, followed by the deposition of bimetals (Cu and Zn) via the thermal evaporation technique on the as-deposited CNTs. The structural properties, surface morphology, elemental composition, and electronic structure were studied using various characterization techniques. The J-E measurements carried out on all the samples revealed that the Cu–Zn–CNTs report a high current density of 9.94 mA/cm² compared to pristine CNTs with 4.01 mA/cm². A thorough study reveals the importance of the electronic structure in varying the current density. Along with the changes in the basic field emission parameters as work function reduction and increase in the field enhancement factor, the electron affinity of individual metal surfaces and their order of coating play a very important role in enhancing the current density for field emission applications.