Enhanced Photodetection with Crystalline Si Nanoclusters

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Silicon oxycarbonitride (SiOₓ) nanodots are crucial for optoelectronic applications.
• Phase separation of SiOₓ is a key method for creating silicon (Si) nanoclusters.
• Titanium dioxide (TiO₂) thin films offer a versatile substrate for nanostructure integration.

Purpose of the Study:

• To fabricate and characterize SiOₓ nanodots on TiO₂ thin films.
• To investigate the structural and optical properties of annealed SiOₓ nanodots for Si nanocluster formation.
• To evaluate the performance of photodetectors fabricated from these materials.

Main Methods:

• Glancing angle deposition (GAD) for SiOₓ nanodot fabrication.
• High-temperature annealing (950 °C) to induce phase separation and Si nanocluster formation.
• Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Atomic Force Microscopy (AFM), Energy Dispersive X-ray (EDX) mapping, and Tauc plot analysis for characterization.

Main Results:

• Annealed samples exhibited Si nanoclusters due to phase separation of SiOₓ nanodots.
• Broadband absorption increased twofold in annealed samples compared to as-deposited ones.
• Photodetectors fabricated from annealed samples showed a twofold increase in dark current and a 1.5-fold increase in light current, attributed to enhanced crystallinity.

Conclusions:

• Annealing SiOₓ nanodots on TiO₂ films effectively generates Si nanoclusters.
• The resulting Si nanoclusters significantly enhance optical absorption and photodetector performance.
• The study demonstrates a promising route for developing advanced optoelectronic devices using Si nanoclusters.