On theory of the indirect coupling photodetection

The paper investigates the theory about indirect coupling photodetection, and points out severe mistakes in its theoretical basis. Experiments show that, excluding the output current created by photo-generated carriers directly diffusing to the output junction, and applying the constant photo-generated voltage across the illuminated open-circuit PN junction, the output current of indirect coupling photodetector approaches the dark current of the output junction, which indicates that the injection current of the illuminated open-circuit PN junction is hard to be extracted.