High-detectivity silver telluride nanoparticle-based near-infrared photodetectors functionalized with surface-plasmonic gold nanoparticles

Herein, the performance of near-infrared (NIR) photodetectors fabricated through a combination of Ag_xTe films comprising colloidal Ag_xTe nanoparticles (NPs) with plasmonic Au NPs was investigated. The surface-plasmonic Au NPs on low-bandgap Ag_xTe considerably enhanced the detectivity of NIR photodetectors. The Au NPs formed on the Ag_xTe surface triggered localized surface-plasmon resonance and increased light absorption, hot-carrier injection, and silver telluride crystallinity during an additional annealing process, which was required to form Au NPs from thermally deposited thin Au layers. Under illumination using an 808-nm laser, the detectivity of the as-fabricated Au NP–decorated Ag_xTe photodetectors was 7.17 × 10¹¹ cmHz^1/2 W⁻¹. Compared with that of pristine Ag_xTe photodetectors, the detectivity of the prepared photodetectors was seven-fold higher; this detectivity was superior to those of devices based on MoS₂, arsenic phosphorus, and SnTe nanoplates and commercial photosensors at room temperature. Thus, the proposed strategy of combining Ag_xTe films with surface-plasmonic Au NPs for enhanced performance of NIR photodetectors provides a new approach for realizing next-generation optoelectronic devices for detection in the NIR region.