Improvement by localized surface plasmon resonance enhancement from Ag nanoparticles in Si-based photodetector

Localized surface plasmon resonance (LSPR) from metal nanoparticles (NPs) has been widely applied to enhance the performance of photodetectors and has been studied by many groups. Due to the limitation of the bandgap, silicon-based (Si-based) devices encounter challenges in sensing infrared region. To overcome this issue, this study discusses how the silver (Ag) NPs to modify Si-based Schottky photodetectors and enhance mid-infrared (MIR) responsivity via rapid thermal annealing (RTA) process by inducing LSPR when illuminating. Under an incident light source at 3460 nm wavelength, the responsivity of the device annealing at 175°C is increased from 0.4481 mA/W to 0.6872 mA/W, which is enhanced 1.533 times compared to device without annealing. In addition, using COMSOL software for electric field intensity simulation confirms that Ag NPs can indeed enhance the electric field intensity to increase the induced LSPR. Therefore, it is demonstrated that the response signal of MIR can be enhanced and amplified by Ag NPs in Schottky devices under the same measurement conditions, achieving the ability to detect MIR region in Si-based Schottky devices.