Colour sensitive devices based on double p-i-n-i-p stacked photodiodes

In this work, we report on an amorphous silicon based image sensor with a bias voltage controllable spectral response characteristics. This multilayered device is composed by two stacked p-i-n-i-p structures produced by plasma enhanced chemical vapour deposition on a glass substrate and sandwiched between two transparent conductive oxide electrodes with a patterned molybdenum layer between the sensing and switching structures. Optical readout technique is used for image readout. Device performances have been evaluated from the current-voltage characteristics and spectral response measurements performed for the p-i-n-i-p test structures and stacked device. It is demonstrated that the device is sensitive to blue-green or red light depending on polarity of the bias voltage enabling the detection of colour images. Device design is discussed and supported by a numerical simulation