How to Characterize Avalanche Photodiode Dark Current

+ Femto / Picoammeters and Electrometers

Measure Avalanche Photodiode Dark Current

Avalanche photodiode (APD) dark-current characterization requires reverse-bias voltage to be applied while the device current is measured with sufficient sensitivity. The device is tested without incident light, and the measurement setup must accommodate the reverse-bias range required by the APD. For high-voltage devices, the source must support the required reverse-bias level while the ammeter resolves the low leakage current.

The measurement is performed by connecting the APD to the voltage source and ammeter, sweeping the reverse-bias voltage, and recording current at each point. The source example uses graphical measurement results to examine the current-voltage behavior, with a pronounced current increase near the high-bias region. Measurement delay is important because stray impedance and dielectric absorption can produce transient leakage after voltage steps; the delay should be long enough for these effects to settle before the current is measured.

Avalanche Photodiode Dark Current Solution

Avalanche photodiode dark-current testing requires a controlled reverse-bias sweep, low-current measurement, and enough settling time after voltage changes to separate device leakage from measurement-path transients. The Keysight B2985C/87C electrometer / high resistance meter combines a voltage source with an ammeter so the reverse-bias voltage can be applied while current is measured synchronously. The Keysight B2985C/87C electrometer / high resistance meter provides 0.01 fA current resolution, current measurement ranges from 2 pA to 20 mA, and voltage sourcing up to 1,000 V, supporting APD evaluation that may require hundreds of volts.

Get Quote

See Block Diagram of Avalanche Photodiode Dark Current Solution

Explore Products in Our Avalanche Photodiode Dark Current Solution

B2985C Electrometer / High Resistance Meter, 0.01 fA

Learn More View Data Sheet
B2987C Electrometer / High Resistance Meter, 0.01 fA, Battery

Learn More View Data Sheet