Which method can improve the performance of a photo diode?

The method that improves the performance of a photodiode is applying reverse bias. When a photodiode is operated in reverse bias, it allows for better collection of photogenerated carriers (electrons and holes) within the semiconductor material. This enhanced collection efficiency leads to a lower dark current, which is the current that flows through the photodiode even in the absence of light. Additionally, operating under reverse bias increases the depletion region width, which enables the photodiode to respond more quickly to incoming light and results in a higher sensitivity.

In comparison, applying a forward bias can actually reduce the effectiveness of a photodiode for light detection, as it may lead to increased dark current and lower impedance. Removing the intrinsic region would also not be beneficial, as this region is crucial for the operation of most photodiodes, affecting their ability to generate and separate charge carriers effectively. Lowering the temperature may help reduce noise in some semiconductor devices but is not a direct method for improving the fundamental operation of a photodiode itself.