Effects of potassium hydroxide post-treatments on the field-emission properties of thermal chemical vapor deposited carbon nanotubes

In this study, a simple potassium hydroxide (KOH) treatment was applied to functionalize the surface and to modify the structures of multi-walled carbon nanotubes (CNTs) grown on silicon substrates by thermal chemical vapor deposition (thermal CVD). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and energy dispersive spectrometer (EDS) were employed to investigate the mechanism causing the modified field-emission properties of CNTs. From our experimental data, it is found that after KOH treatment the emitted currents were enhanced by more than one order of magnitude compared with those of the untreated CNTs. The emitted current density of CNTs increases from 0.44 mA/cm² to 7.92 mA/cm² after 30 minutes of KOH solution treatment. This method provides a simple, economical, and effective way to enhance the CNT field-emission properties.