High-Performance Planar Broadband Hot-Electron Photodetection through Platinum-Dielectric Triple Junctions

Area of Science:

• Optoelectronics
• Materials Science

Background:

• Previous planar hot-electron photodetectors (HE PDs) suffered performance degradation.
• Single-junction designs and thick films limited device efficiency.

Purpose of the Study:

• To develop a high-performance planar HE PD with broadband absorption.
• To overcome limitations of previous single-junction HE PD designs.

Main Methods:

• Designed a five-layer HE PD structure utilizing triple junctions.
• Employed an ultrathin platinum (Pt) layer for broadband absorption.
• Utilized optical admittance matching for enhanced light trapping.

Main Results:

• Achieved strong optical absorption (>0.9) from 900 nm to 1700 nm.
• Predicted responsivity up to 8.51 mA/W at 900 nm.
• Demonstrated sustained high absorption and responsivity across wide incidence angles and polarizations.

Conclusions:

• The five-layer design significantly enhances optical absorption in Pt layers.
• Triple junctions improve hot-electron extraction efficiency compared to three-layer devices.
• The proposed HE PD design offers superior performance for broadband detection.