Comparison of the quantum efficiency and the responsivity of the single-walled carbon nanotube photodetector with different electrode metals

Abstract

In this paper, experimental measurements of the photoconductivity in single-walled carbon nanotube (SWCNT) thin films were taken using four different electrodes (Pt, Pd, Au and Ti). Our work shows the impact of the light power intensities and wavelengths on the photoresponse signal. In this context, we have performed the electrical transport characteristics of the device at room temperature under visible continuous wavelength illumination. The photoconductivity measurements, achieved without gating, have shown a strong photoresponse enhancement at the nanotubes/electrode junctions. The obtained response has been generally attributed to the dissociation and subsequent diffusion of photoexcited carriers. We have also proven that a good choice of the metal electrode evidently enhances the photoconductivity of SWCNT-thin film. Due to its high work function and its excellent adhesivity on the thin film of SWCNTs, Au electrodes have shown the most important results than the others metals. The highest quantum efficiency ( $$ \eta $$ ) calculated in our case is about 12%, and the responsivity reaches 121.48 mA/W for Au–SWCNT contact.