Large area hydrogenated amorphous silicon p-i-n structures with low conductivity doped layers were proposed as single element image sensors. This work is focused on the analysis of the dynamic behavior of the sensor. Additionally some sensor parameters like maximum scanning speed, from which depends the maximum achievable frame rate are presented and discussed.
In order to evaluate the sensor response to a time varying light excitation the sensor was locally illuminated with a focused chopped light source and the generated photocurrent was measured under different load conditions. Results show that the sensor is mainly capacitive and a signal rise time of approximately 100 νs was measured under a 1 kΩ load. A model for the sensor was created from the experimental data and was used to simulate the dynamic behavior of the sensor. The simulation results obtained are in good agreement with the experimental ones.
As conclusion one can expect a trade off between the frame rate and the number of pixels. A frame rate higher than 10 fps was achieved for 100×100 pixels readout without a significant degradation in the image quality.