Two-Color Infrared Sensor on the PbTe: In p-n Junction

Area of Science:

• Materials Science
• Semiconductor Physics
• Infrared Technology

Background:

• Development of high-temperature mid-infrared (mid-IR) sensors is crucial for various applications.
• Lead telluride (PbTe) is a promising material for IR detection.
• Existing PbTe sensors often require cryogenic cooling, limiting their practical use.

Purpose of the Study:

• To fabricate and characterize a novel high-temperature mid-IR sensor based on lead telluride (PbTe).
• To demonstrate the feasibility of operating a PbTe diode at temperatures accessible by thermoelectric coolers.
• To investigate the photovoltaic properties of PbTe, including two-photon absorption.

Main Methods:

• Fabrication of a PbTe p-n junction sensor using the Czochralski growth technique and indium diffusion.
• Measurement of capacitance-voltage and current-voltage characteristics between 80 K and 150 K.
• Demonstration of sensing capabilities for mid-IR and long-IR radiation pulses.

Main Results:

• A prototype PbTe diode mid-IR sensor with a 4 μm cut-off wavelength, operational up to 150 K, was successfully demonstrated.
• The sensor achieved a specific detectivity of 10^10 cm Hz^1/2/W at 150 K and 4.2 μm.
• A novel two-photon absorption-induced photovoltaic effect in PbTe was observed at 9.5 μm and 150 K.

Conclusions:

• The developed PbTe diode represents a significant advancement in high-temperature mid-IR sensing.
• Its operating temperature is compatible with solid-state thermoelectric cooling, enhancing practical applications.
• The observation of the two-photon photovoltaic effect opens new avenues for IR detection mechanisms in PbTe.