Visible-light phototransistors based on InGaZnO and silver nanoparticles

Abstract

Visible-light phototransistors were fabricated using wide-bandgap indium gallium zinc oxide (IGZO) and silver (Ag) nanoparticles (NPs). A bottom gate made of thin film transistors (TFTs) was fabricated with an amorphous IGZO film as the active channel. Ag NPs were then formed on the surface of the active channel region to be used as a visible-light absorption layer. The prepared Ag NPs were highly absorptive in the wavelength range of 450-600 nm, due to the plasmon effect. A detailed study of photoresponsivity and external quantum efficiency indicated that the TFTs with Ag NPs induced a large photocurrent upon illumination by visible light on the active region, while the TFTs without Ag NPs did not. This result indicates the presence of coupling between the localized plasmons and electrical carriers on the IGZO TFTs with Ag NPs.