Excellent field emission with enhanced photodetection behavior of multiwalled carbon nanotubes: experimental and theoretical study

Abstract

In this study, we synthesized multiwalled carbon nanotubes (MWCNTs) using the direct liquid injection chemical vapor deposition (DLICVD) method, the growth temperatures were varied to investigate their unique properties. To fully characterize these MWCNTs, we examined their surface morphology utilizing scanning electron microscopy (SEM). Additionally, we used UV-visible spectroscopy to evaluate their energy band gap, which provided insight into their electrical characteristics. The most remarkable results of our study were the impressive field emission properties of the MWCNTs. Specifically, they exhibited an extraordinarily low emission threshold field of approximately 0.1 V μm⁻¹, showcasing their potential for advanced electron emission applications. In addition, these MWCNTs demonstrated a remarkably high current density of roughly 1 mA cm⁻², which emphasized their superior electrical conductivity. Expanding the scope of our investigation, we integrated MWCNT-based thin films into photodetector devices, which opened up exciting possibilities in optoelectronics. Under an illumination intensity of 25 mW cm⁻², these devices exhibited a maximum responsivity of 1.031 A W⁻¹, illustrating their sensitivity to incoming light. Furthermore, our research highlights the excellent detectivity of these MWCNT-based photodetectors, measuring an impressive 2.178 × 10¹⁰ jones under the same illumination conditions. The remarkable performance of the MWCNT-based photodetector device extended to its external quantum efficiency, which reached an astonishing 174.9%.