Blue-enhanced thin-film photodiode for dual-screen x-ray imaging

This article reports on a -Si : H -based low-leakage blue-enhanced photodiodes for dual-screen x-ray imaging detectors. Doped nanocrystalline silicon was incorporated in both the n - and p -type regions to reduce absorption losses for light incoming from the top and bottom screens. The photodiode exhibits a dark current density of 900 pA / cm 2 and an external quantum efficiency up to 90% at a reverse bias of 5 V. In the case of illumination through the tailored p -layer, the quantum efficiency of 60% at a 400 nm wavelength is almost double that for the conventional a -Si : H n - i - p photodiode.