Photomodulation of InGaZnO thin film transistors with interfacial silver nanoparticles

Abstract

Silver nanoparticles (Ag NPs) were inserted between indium gallium zinc oxide (IGZO) and a gate insulator to enhance the generation of plasmonic photocurrent with the illumination of visible light. Ag NPs were formed on a silicon dioxide gate insulator using a thermal evaporator and a post-annealing process. Then, an amorphous IGZO active channel layer was deposited on the Ag NPs using a sputter system. The prepared Ag NPs effectively absorbed a wide wavelength range of visible light due to plasmon effects. The IGZO thin film transistors (TFTs) with interfacial Ag NPs showed a large photocurrent due to the strong coupling between localized plasmons and electrical carriers in the active channel region of the TFTs. The prepared device showed good modulation behavior under visible light even though IGZO has a wide band gap. The results indicate that interfacial Ag NPs enabled the photomodulation of IGZO TFTs when exposed to a periodic signal of low-energy visible light. This work demonstrates a useful way to develop visible-light phototransistors based on a wide band gap semiconductor and plasmonic Ag NPs. (C) 2016 The Japan Society of Applied Physics