In regard to the reverse biased pn junction photodiode the following statements are made—
1. The photon current and the saturation current are in the same direction.
2. While the photon current is essentially due to minority carriers, the saturation current is due to majority carrier flow.
3. The number of electron hole pairs due to illumination is proportional to the number of incident photons.
4. The effect of illumination can be considered as a majority carrier injection.
Of the four statements, the true statements are—