Synergistic Contribution of Surface Plasmon and Passivation to High-Performance Solar-Blind UV Optical-Communication Sensor

With the incorporation of indium (In), the surface energy band of (In0.25Ga0.75)2O3 (InGaO) bends upward, leading to mitigating electron loss. The thin MgO layer optimizes optical performance and improves resonance quality factor by reducing losses. Here, Ag nanoparticles (AgNPs) coated by a 10-nm thick MgO layer were fabricated on3InGaO films. By localized surface plasmon resonance (LSPR) effect of AgNPs, the enhanced optical properties of MgO, and high-k dielectric passivation, a high-performance solar-blind photodetector was achieved. This photodetector demonstrated high responsivity (R), detectivity ( ${D}^{\ast }$ ), and external quantum efficiency (EQE) of 2438.8 mA/W, $2.4\times 10^{{14}}$ Jones, and 1193.6%, respectively, significantly improving the detection performance of the InGaO thin films fabricated by plasma enhanced chemical vapor deposition (PECVD). In addition, the InGaO@AgNPs/MgO is integrated into optical communication systems as a signal receiver and implements ASCII communication with minimal power consumption and weak light intensity. This work presents a straightforward and efficient method for significantly enhancing the performance of detectors, facilitating their applications in the fields of the Internet of Things (IoT) and optical sensing.