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 AgxTe films comprising colloidal AgxTe nanoparticles (NPs) with plasmonic Au NPs was investigated. The surface-plasmonic Au NPs on low-bandgap AgxTe considerably enhanced the detectivity of NIR photodetectors. The Au NPs formed on the AgxTe 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 AgxTe photodetectors was 7.17 × 1011 Hz1/2 W−1. Compared with that of pristine AgxTe 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 AgxTe 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.