How does reverse biasing enhance the performance of a photo diode?

Reverse biasing a photodiode enhances its performance primarily by creating a stronger electric field within the depletion region. When a reverse bias voltage is applied, it increases the potential difference across the junction, which strengthens the electric field. This increased electric field is crucial because it facilitates the separation of electron-hole pairs that are generated when the photodiode is exposed to light.

The enhanced electric field helps in quickly sweeping the generated charge carriers (electrons and holes) away from the junction, reducing the likelihood of recombination before they contribute to the current. This leads to improved responsivity and faster response times of the photodiode, making it more effective in converting light into an electrical signal.

While it is true that reverse bias can affect the other factors mentioned in the options, such as altering the depletion region width or affecting the active region's characteristics, the primary and most significant benefit comes from the strong electric field that promotes efficient charge carrier movement and enhances the overall performance of the photodiode.