Optimization of a-Si : H-based three-terminal three-color detectors

Three-terminal three-color a-SiC:H/a-Si:H-based TCO/PINIP/TCO/PIN/metal det ectors are presented. Assemblies having different surface roughness of tran sparent conducting oxide (TCO) layers are compared with regard to the exter nal steady-state characteristics and transient behavior. The roughness of t he sputtered TCO surface can be modified by an etching treatment, With the selection of smooth or textured TCO surfaces, the wave propagation of light within the device is controlled, This design technique can be exploited to optimize the color separation and improve the reproducibility of spectral responsivities in the assemblies. The examined assemblies exhibit very sele ctive spectral responsivity for the fundamental chromatic components (red-g reen-blue) and a linear photocurrent-generation rate relationship over more than five orders of magnitude of illumination intensity. Since the color d etection of blue and green light is performed in the PINIP structure by bia s switching, the transient current response of the PINIP structures is inve stigated. A reciprocal relationship between the delay time and illumination intensity is established. An optimum operation region for the switching vo ltages is determined with regard to the quality of color separation, dynami c range, and transient behavior.