Hydrogenated Nanocrystalline Silicon Near Infrared Photodiode Detector

This letter reports on fabrication of a low-cost high-dynamic range near infrared (NIR) photodiode detector on glass substrate using thin films of hydrogenated nanocrystalline silicon (nc-Si:H) prepared by 13.56-MHz plasma-enhanced chemical vapor deposition. The fabricated device shows more than two orders of magnitude enhancement in external quantum efficiency compared with the conventional hydrogenated amorphous silicon (a-Si:H) photodiode in the wavelength region of 830-950 nm. The short circuit dark current density of the nc-Si:H device is 22.3 nA/cm
²
, which is only four times higher than that of a-Si:H photodiode. As a result, the dynamic range of operation for nc-Si:H device is at least 35 times higher than its amorphous counterpart in the wavelength region of interest, making it suitable for digital NIR imaging applications.