Optimized Three-Color Detector Based on a-SiGe:H Heterojunctions

Abstract

AbstractBandgap and μτ - (carrier mobility x lifetime) - engineered multi-color nipin detectors with three linear independent curves of the spectral response in a range from 470nm to 670nm are successfully fabricated. The spectral response of nipin structures employed as two terminal devices shifts by the applied voltage. Switching transients after changing the color sensitive voltages under different monochromatic illumination conditions are investigated and can be classified in different cases. In order to improve the understanding of the photo current transients, we have characterized the influence of different illumination conditions on the voltage dependent capacitance behavior. To verify the capacitance measurements, a SPICE model has been developed, which describes the transient behavior of the detector. The simulations are in good agreement with the experimental data and support the explanation of the transient cases after bias switching. Based on these results further optimization criteria to accelerate the transient behavior are presented.