TiO2 embedded Si nanowire network based Schottky detector for enlarged light detection

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Silicon nanowires (Si NWs) offer unique electronic and optical properties.
• Titanium dioxide (TiO2) is a promising material for optoelectronic applications.
• Improving the performance of photodetectors is crucial for various sensing technologies.

Purpose of the Study:

• To fabricate a silicon nanowire network using glancing angle synthesized silver nanoparticles (Ag NPs) assisted etching.
• To deposit a TiO2 thin film (TF) on the Si NWs and characterize its optical and electrical properties.
• To evaluate the photodetection performance of the TiO2-Si NW device and compare it with a TiO2 TF device.

Main Methods:

• Fabrication of Si NW network via Ag NPs assisted etching.
• Characterization using field emission gun-scanning electron microscopy (FEG-SEM).
• Optical absorption measurements and photoconduction studies under illumination.

Main Results:

• Formation of Si NWs with diameters of 110-180 nm.
• TiO2 deposition enhanced optical absorption by 2.5 times compared to bare Si.
• TiO2-Si NW detector exhibited higher photoconduction and threefold enhanced photodetection versus TiO2 TF.
• Dark currents were 0.1 mA/cm² (TiO2 TF) and 0.2 mA/cm² (TiO2-Si NW), increasing to 0.2 mA/cm² and 1.23 mA/cm² under illumination, respectively.

Conclusions:

• The TiO2-Si NW structure demonstrates superior photodetection capabilities.
• Ag-TiO2 contacts exhibit Schottky behavior, contributing to device performance.
• Carrier diffusion effects influence the photocurrent response in the Si NW device.