Transient behavior of optimized nipiin three-color detectors

Abstract

The detection of the fundamental components of the visible light (blue, green, red) is realized with a multispectral photodiode based on amorphous silicon. The preferential carrier collection region of this two-terminal device shifts upon changing the applied bias voltage, which leads to a color sensitivity. Structures with controlled bandgap and mobility-lifetime product exhibit a dynamic behavior above 95 dB. Three linearly independent spectral response curves can be extracted to generate a RGB-(red-green-blue)-signal. Bias voltage switching experiments under different monochromatic illumination conditions are carried out to investigate the time-dependent behavior. Furthermore, in order to improve the understanding of the photocurrent transients, we have characterized the voltage-dependent capacitance behavior, Thus, a Simulation Program with Integrated Circuit Emphasis (SPICE) model including the capacitance-voltage (CV) data has been developed, which describes the transient behavior of the detector. The simulations are in good agreement with the experimental data and allow an interpretation of the transient photocurrent response after bias voltage switching. Based on these results, optimization criteria to improve the transient behavior are discussed.