Multidecade linearity measurements on Si photodiodes.

Area of Science:

• Photodetector characterization
• Semiconductor device physics
• Metrology and instrumentation

Background:

• Silicon photodiodes are widely assumed to exhibit linearity over extensive ranges.
• Experimental verification of this linearity, particularly across multiple decades, is scarce in scientific literature.
• Understanding photodiode linearity is crucial for accurate optical measurements and sensor applications.

Purpose of the Study:

• To experimentally investigate and verify the linearity of silicon (Si) photodiodes.
• To extend the verification of linearity over the widest possible range of operational decades.
• To provide empirical evidence supporting or refuting the claimed wide-range linearity of Si photodiodes.

Main Methods:

• Employed a cascaded linearity tester based on Sanders' double-aperture method for optical measurements.
• Utilized electronic instrumentation including an operational amplifier, a voltage-to-frequency converter, and a counter.
• Conducted measurements on Si photodiodes from multiple manufacturers.

Main Results:

• Measurements successfully covered a broad range of approximately nine decades, from 10 mA down to 10 pA.
• The study presents detailed results of the linearity tests performed on various Si photodiodes.
• The experimental data provides a comprehensive assessment of photodiode performance across a vast current range.

Conclusions:

• The experimental investigation provides critical data on the linearity of silicon photodiodes.
• The findings contribute to the body of evidence regarding the operational range and reliability of Si photodiode detectors.
• This research validates the performance characteristics of Si photodiodes for precise optical sensing applications.