| dc.description.abstract | Infrared detectors are commonly applied in various fields, such as security monitoring, biometric identification, and digital healthcare. Silicon is the most commonly used material in optical sensors, and fabrication of rough structures and nanowires on Si are known to increase the light trapping ability of visible light. However, the bandgap limitation of silicon at 1.12 eV makes it unable to effectively absorb infrared light. In order to overcome this shortcoming, this study introduced the copper/silver metal-assisted chemical etching method for the first time to prepare a micron-scale inverted-pyramid structure, followed by the fabrication of straight silicon nanowires (SiNWs) on the surface of the structure, forming an extensive SiNWs/inverted-pyramid dual-scale structure. Then, Ag nanoparticles (AgNPs) are deposited on the SiNWs using a non-electroplating technique, improving the absorption efficiency of visible and infrared light through surface plasmon resonance effects, the high light-trapping efficiency and large specific surface area of the nano-microstructure. The results of UV-Vis and NIR spectroscopic measurements confirmed that the structure has broadband light absorption characteristics from the visible to near-infrared region (400-1600 nm). Moreover, the results of photo-sensing properties at 940 nm near-infrared light further indicate that our novel silicon photodetector exhibits high near-infrared photo responsivity, good stability, and fast response and recovery time without applying additional voltage.
In order to fabricate ultra-thin and flexible photodetector, this study successfully formulated a copper metal-assisted-etching solution and simultaneously created grooved structures on the silicon surface while thinning the samples. By applying the aforementioned fabrication techniques, ultra-thin silver/silicon Schottky junction photodetectors were successfully developed. It is believed that the simple and original copper/silver metal-assisted chemical etching method of dual-scale structures and electroless plating technology developed in this study can provide a reference for new process design and technology optimization for the development of various advanced silicon-based optoelectronic devices and broadband photodetectors.
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