High Performance CMOS Light Detector with Dark Current Suppression in Variable-Temperature Systems.

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Sensor Technology

Background:

• Dark current in photodetectors impacts performance, especially in variable-temperature environments.
• Existing photoresistors (epichlorohydrin, cadmium sulphide) exhibit limitations in dark current suppression.
• Infrared light-emitting diodes in variable-temperature systems exacerbate dark current issues.

Purpose of the Study:

• To present a novel dark current suppression technique for light detectors.
• To improve the performance of light detectors in variable-temperature systems.
• To offer a superior alternative to existing photoresistor technologies.

Main Methods:

• Designed a light detector architecture incorporating a photodiode, dark current diode, and current subtractor.
• Integrated the dark current suppression circuitry within a current amplifier.
• Conducted experimental measurements of dark current and linearity across various temperatures.

Main Results:

• The proposed light detector demonstrates lower measured dark current than epichlorohydrin or cadmium sulphide photoresistors.
• Near-zero dark current (< 9.23 nA) achieved at temperatures below 50 °C.
• Maximum dark current of approximately 135 nA at 125 °C; exponential relationship observed above 50 °C.
• Linearity of ~1.15 μA/lux at 10 kΩ external resistance across 25 °C to 85 °C.

Conclusions:

• The developed dark current suppression technique effectively enhances light detector performance in variable-temperature conditions.
• The proposed detector offers a significant advantage over conventional photoresistors for applications with infrared light sources.
• The design provides reliable and accurate light detection across a wide temperature range.