Influence of carbon nanotube suspensions on the structural, optical, and electrical properties of grown ZnO nanorods

Zinc oxide (ZnO) nanostructures have shown remarkable potential in optoelectronics applications due to their outstanding optical and electronic properties. Doping ZnO with nanomaterials such as metal nanoparticles has proven its effectiveness in altering, enhancing, and modifying the intrinsic ZnO to suit the intended application. However, doping ZnO with certain materials, such as carbon nanotubes (CNTs), is much more challenging due to their chemical inactivity and low dispersity in mediums. In this work, ZnO nanorods (ZNRs) were grown on ITO-coated glass substrate using the chemical bath deposition (CBD) method, followed by doping the ZNRs with CNTs suspended in different organic solvents using the drop-casting method. The doped ZNRs were characterized using several characterization methods, including AFM, FESEM, EDX, UV–Vis, PL, and I–V. From the results, it was found that low yield integration of CNTs within the ZNRs was achieved when dimethylformamide (DMF) and ethanol (ETH) were used as solvents, whereby the doped ZNRs were observed to possess similar optical behavior. Results from the other solvent, 1,2-Dichloroethane (DCE), revealed structural damage to the ZNRs, and CNTs were found to merge with the ZNRs, forming a surface with large-size grains. Meanwhile, doping CNTs from acetone (ACE) solvent shows a promising result whereby an acceptable amount of CNTs were well integrated within the ZNRs with minimum structural damage. It was found that the roughness, average diameter, Zn:O:C ratio, band gap energy, and emission peak of the ZNTs doped with CNTs from ACE were 35.2, 57.89 nm, 46:38:16, 3.23 eV, 381.55 nm, respectively. This is the first study that focuses on doping ZNRs with CNT through drop-casting without degrading the electrical and optical properties of the ZNRs. We believe that CNT-doped ZNRs have excellent potential as gain media in electrically pumped random lasers due to the combination of the optical properties of ZnO and the electrical properties of the CNTs.