Large area p-i-n flexible image sensors


Large area p-i-n image sensors deposited on plastic substrates were produced at low temperatures (110 °C) by PE-CVD and compared with similar sensors deposited on glass substrates. The same sensing element structure ZnO:Al/p(SiC:H)/i(Si:H)/n(SiC:H)/Al was used for both devices. In this work the efforts are focused mainly on the optimization of the output characteristics of the sensor when fabricated on plastic substrates. The role of the sensor configuration and readout parameters in the image acquisition process is analyzed. The optical- to-electrical transfer characteristics show a reasonable quantum efficiency under a red light pattern, broad spectral response, and reciprocity between light and image signal.

First results show that the sensors deposited on flexible substrate present smaller light to dark sensitivity than those deposited on glass. In both, the non ohmic behavior of the transparent conductive oxide front contact blocks the carrier collection and leads to a surprising linear dependence of the image signal with the applied voltage.

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This work has been financially supported by FLAD, Fundação Calouste Gulbenkian and POCTI/ESE/38689/2001 project.

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Vieira, M., Louro, P., Fernandes, M. et al. Large area p-i-n flexible image sensors. MRS Online Proceedings Library 814, 260–265 (2004).

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