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A real-time optical signal and image processing p-i-n/p-i-n device

Published online by Cambridge University Press:  21 March 2011

M. Vieira
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
P. Louro
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
M. Fernandes
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
A. Fantoni
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
C. Mendes
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
J. Martins
Affiliation:
Electronics Telecommunication and Computer Dept. ISEL, Rua Conselheiro Emídio Navarro, P 1949-014 Lisboa, Portugal Tel: +351 21 8317290, Fax: +351 21 8317114, mv@isel.ipl.pt
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Abstract

Large area (4x4 cm2) optical signal and image processing (OSIP) devices were produced at low temperatures (110°C) by PE-CVD. The OSIP device consists of two stacked sensing/switching diodes (p(SiC:H)/i(Si:H)/n(SiC:H)) with or without an internal blocking layer between them and two semitransparent contacts. An optical scanner is used for charge readout. In this work the main emphasis will be put on the analysis of the optical characteristics. The use of a metal grid (290x290 μm2 Cr pixels with 40 m m spacing) between the two diodes, working as light screening layer or as floating anode via an a-SiN insulator layer, is analyzed. Its influence on the transfer functions, resolution, responsivity and response time of the sensor is presented. The various design parameters trade-offs are discussed. The optical-to-electrical transfer characteristics show high quantum efficiency, broad spectral response, and reciprocity between the optical and the electrical images. When the light screening floating anode is present an effective optical decoupling from both photodiodes is achieved while maintaining a good electrical conductivity and an increased light-to-dark sensitivity. A trade-off is established between sensor design and light pattern and scanner wavelengths in order to minimize the cross talk between the write and the read beams and to improve the light to dark sensitivity.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

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