TeSe_1- Shortwave Infrared Photodiode Arrays with Monolithic Integration

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• TeSe_1- based shortwave infrared (SWIR) photodetectors offer potential for cost-effective monolithic integration with readout integrated circuits (ROIC).
• High dark current density and insufficient detection performance are key challenges limiting their large-scale application.
• Conventional SWIR photodetectors are often expensive, driving the need for alternatives.

Purpose of the Study:

• To develop a ZnO/TeSe_1- heterojunction photodiode with improved performance for SWIR detection.
• To address interfacial issues like elemental diffusion and dangling bonds in TeSe_1- photodetectors.
• To demonstrate the feasibility of large-scale monolithic integration of these photodetectors with ROIC.

Main Methods:

• Fabrication of ZnO/TeSe_1- heterojunction photodiode with an amorphous TeO₂ interfacial layer (0.3 nm).
• Characterization of photodetector performance including dark current density, spectral response, detectivity, and bandwidth.
• Monolithic integration of the optimized TeSe_1- photodiodes onto a 64 × 64 pixel ROIC.
• Demonstration of application in transmission imaging and substance identification.

Main Results:

• Reduced dark current density to -3.5 × 10^-5 A cm^-2 at -10 mV.
• Broad spectral response from 300 to 1700 nm.
• Room-temperature detectivity exceeding 2.03 × 10¹¹ Jones and a 3 dB bandwidth of 173 kHz.
• Successful monolithic integration of the largest-scale TeSe_1- photodiode array on ROIC to date.
• Demonstrated utility in transmission imaging and substance identification.

Conclusions:

• The optimized ZnO/TeSe_1- heterojunction photodiode with a TeO₂ interlayer effectively overcomes performance limitations.
• This work represents the first successful large-scale monolithic integration of TeSe_1- photodiodes on ROIC.
• The developed photodetectors show significant promise for advanced SWIR imaging applications.