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Time of Flight of Drifting Electrons and Holes in Stabilized a-Se Film

Published online by Cambridge University Press:  01 February 2011

Dong-Gil Lee
Affiliation:
Department of Biomedical Engineering, College of Biomedical Science and Engineering Inje University, Kimhae, Kyungnam, 621-749, Korea
Ji-Koon Park
Affiliation:
Department of Biomedical Engineering, College of Biomedical Science and Engineering Inje University, Kimhae, Kyungnam, 621-749, Korea
Jang-Yong Choi
Affiliation:
Department of Biomedical Engineering, College of Biomedical Science and Engineering Inje University, Kimhae, Kyungnam, 621-749, Korea
Jae-Hyung Kim
Affiliation:
Medical Imaging Research Center Inje University, Kimhae, Kyungnam, 621-749, Korea
Sang-Hee Nam
Affiliation:
Medical Imaging Research Center Inje University, Kimhae, Kyungnam, 621-749, Korea
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Abstract

Large area, flat panel detectors are being investigated for digital radiogrpahy and fluoroscopy. Theses detectors employ an x-ray conversion layer of photoconductor to detect x-rays. The amorphous selenium layer that is currently being studied for its use as an x-ray photoconductor is not pure a-Se but rather a-Se doped with 0.2-0.5% As and 10-30 ppm Cl, also known as stabilized a-Se. The suitability of the stabilized a-Se is largely determined by its charge on generating, transporting and trapping properties.

In this paper, a conventional time-of-flight measurement was carried out to analyze the transport properties of charge carriers. A laser beam with pulse duration of 5 ns and wavelength of 350 nm was illuminated on the surface of the stabilized a-Se with thickness of 400 μm. The photo response signals of the hole and electron were measured at the applied electric field of 10 V/μm as a function of time. The measured transit times of the hole and electron were about 229.17μs and about 8.73μs at 10 V/μm, respectively. The measured mobility indicated a slight dependence with respect to the applied electric field with a range of 4-10 V/μm. The experimental results showed that the measured mobility of the hole and electron was 0.04584 cm2V-1s-1 and 0.00174 cm2V-1s-1 at the electric field of 10 V/μm.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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References

1. Boag, J. W., Xeroradiography, Phys. Med. Biol. 1973;18:337 Google Scholar
2. Kasap, S. O., Photoreceptors: The Selenium Alloys: Arthur S. Diamond: Marcel Dekker, 1991:329-372Google Scholar
3. Haugen, C., Kasap, S.O., and Rowlands, J. Charge Transport And Electron-Hole Pair Creation Energy In Stabilized a-Se X-Ray Photoconductors. 1999;32: 200207 Google Scholar
4. Polischuck, B., Kasap, S.O., Viswanath, Aiyah, Baillies, A., Int. J. Electron. 1994;76:1029 Google Scholar
5. Antonuk, L. E., Mohri, Y. E., Jee, K. W., Zhao, Q., Sawant, A., and Su, Z., Proceedings of SPIE, Vol. 4682, 1 (2002) C3.53.7 Google Scholar
6. Mikla, V. I., Phys. stat. Sol. (a), 165, 427 (1998)Google Scholar
7. Choquette, M., Rougeot, H., Martin, J. P., Laperriere, L., Shukri, Z. and Polischuk, Brad., Proceedings of SPIE, Vol. 3977, 128 (2000)Google Scholar
8. Que, W., and Rowlands, J. A., Med. Phys., Vol. 22, No. 4, 365 (1995).Google Scholar
9. Haugen, C., Kasap, S. O., and Rowlands, J., Appl. Phys., 32, 200 (1999)Google Scholar
10. Zhang, Q. and Champness, C. H., Can. J. Phys., 69, 278 (1990)Google Scholar
11. Haugen, C., Kasap, S. O., and Rowlands, J.., J. Phys. D: Appl. Phys. Vol. 32, 200 (1999).Google Scholar