Hostname: page-component-848d4c4894-5nwft Total loading time: 0 Render date: 2024-05-22T06:53:56.959Z Has data issue: false hasContentIssue false
  • English
  • Français

UPS of a-Si:H<Er>: What is the energy of the Er 4f states?

Published online by Cambridge University Press:  17 March 2011

Leandro R. Tessler ,
Cínthia Piamonteze ,
Ana Carola Iniguez ,
Abner de Siervo ,
Richard Landers  and
Jonder Morais
Leandro R. Tessler
Affiliation:
Instituto de Física “Gleb Wataghin”, UNICAMP, C. P. 6165, 13083-970 Campinas, SP, Brazil
Cínthia Piamonteze
Affiliation:
Instituto de Física “Gleb Wataghin”, UNICAMP, C. P. 6165, 13083-970 Campinas, SP, Brazil
Ana Carola Iniguez
Affiliation:
Instituto de Física “Gleb Wataghin”, UNICAMP, C. P. 6165, 13083-970 Campinas, SP, Brazil
Abner de Siervo
Affiliation:
Instituto de Física “Gleb Wataghin”, UNICAMP, C. P. 6165, 13083-970 Campinas, SP, Brazil
Richard Landers
Affiliation:
Instituto de Física “Gleb Wataghin”, UNICAMP, C. P. 6165, 13083-970 Campinas, SP, Brazil
Jonder Morais
Affiliation:
Laboratório Nacional de Luz Síncrotron, C. P. 6093, 13083-970, Campinas, SP, Brazil
Get access

Abstract

One very important problem concerning erbium-doped silicon is the electronic structure of the Er3+ impurities. In particular, it is still not clear if the 4f levels can be treated as frozen core levels or their overlap with s and p states of their neighbors must be considered explicitly. For crystalline Si, the 4f levels have been supposed to be anywhere between 20 eV below the valence band and within the energy gap. In this paper we report on the first ultraviolet photoemission spectroscopy (UPS) measurements on Er-doped a-Si:H. Samples of a-Si:H<Er> with different Er contents (up to 1 at. % Er) were prepared by co-sputtering from a Si target partially covered with metallic Er platelets. In order to enhance the Er states relative to the Si and H states, the excitation energy was tuned between 40 and 140 eV with a synchrotron light source. At 140 eV excitation energy the cross-section of the Er 4f and 5p states is more than an order of magnitude higher than the cross section of the Si 3s or 3p states. As the Er concentration increases, a shoulder and then a peak appears at 10.0±0.5 eV binding energy. The intensity and width of this peak is well correlated with the Er concentration, and with the Er 5p and 5p½ levels at 26 and 32 eV binding energy, respectively. We attribute the peak at 10.0±0.5 eV binding energy to the Er 4f level. These are the only occupied states that can be related to the presence of Er, indicating that these levels are not valence states and consequently can be treated as frozen core levels.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 609: Symposium A – Amorphous & Heterogeneous Silicon Thin Films – 2000 , 2000 , A11.1
Copyright
Copyright © Materials Research Society 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Rare Earth Doped Semiconductors, ed. Pomrenke, G. S., Klein, P. B. and Langer, D. W., (Mater. Res. Soc. Proc. 301, Pittsburgh, 1993); Rare Earth Doped Semiconductors II, ed. A. Polman, S. Coffa and R. Schwartz, (Mater. Res. Soc. Proc. 422, Pittsburgh, 1996).Google Scholar
2. Coffa, S., Franzò, G., Priolo, F., Polman, A. and Serna, R., Phys. Rev. B 49, 16313 (1994).Google Scholar
3. Zanatta, A. R., Nunes, L. A. O. and Tessler, L. R., Appl. Phys. Lett. 70, 511 (1997).Google Scholar
4. Tessler, L. R. and Iniguez, A. C., in Amorphous Silicon Technology -1998, ed. Wagner, S., Hack, M., Branz, H. M., Schroop, R. and Shimizu, I., (MRS Symp. Proc. 507, Pittsburgh, PA 1998), pp. 327–332.Google Scholar
5. Shin, J. H., Serna, R., Hoven, G. N. van den, Polman, A., Sark, W. G. J. H. M. van and Vredenberg, A. M., Appl. Phys. Lett. 68, 997 (1996).Google Scholar
6. Terukov, E. I., Kon'kov, O. I., Kudoyarova, V. Kh., Gusev, O. B. and Weiser, G., Semiconductors 32, 884 (1998) [Fiz. Tekh. Poluprovodn. 32, 987 (1998)].Google Scholar
7. Bressler, M. S., Gusev, O. B., Kudoyarova, V. Kh., Kuznetsov, A. N., Pak, P. E., Terukov, E. I., Yassievitch, I. E., Zakharchenya, B. P., Fuhs, W. and Sturm, A., Appl. Phys. Lett. 67, 3599 (1995).Google Scholar
8. Michel, J., Benton, J. L., Ferrante, R. F., Jacobson, D. C., Eaglesham, D. J., Fitzgerald, E. A., Xie, Y.-H, Poate, J. M. and Kimerlingh, L. C., J. Appl. Phys. 70, 2672 (1991).Google Scholar
9. Masterov, V. F., Nasredinov, F. S., Seregin, P. P., Kudoyarova, V. Kh., Kuznetsov, A. N. and Terukov, E. I., Appl. Phys. Lett. 72, 728 (1998)Google Scholar
10. Piamonteze, C., Iniguez, A. C., Tessler, L. R., Alves, M. C. Martins and Tolentino, H., Phys. Rev. Lett. 81, 4652 (1998).Google Scholar
11. Tessler, L. R., Piamonteze, C., Iniguez, A. C., Alves, M. C. Martins and Tolentino, H., in Applications of Synchrotron Radiation Techniques to Materials Science IV, ed. Mini, S. M., Perry, D. L., Stock, S. R. and Terminello, L. J., (Mat. Res. Soc. Proc. 524, Pittsburgh, 1998), pp. 327–332.Google Scholar
12. Delerue, C. and Lanoo, M., Phys. Rev. Lett. 67, 3006 (1991).Google Scholar
13. Needels, M., Schlüter, M. and Lanoo, M., Phys. Rev. B 47, 15533 (1993).Google Scholar
14. Yassievich, I. N. and Kimerling, L. C., Semicond. Sci. Technol. 8, 718 (1993)Google Scholar
15. Michel, J., Assali, L. V. C., Morse, M. T. and Kimerling, L. C., in Semiconductors and Semimetals 49, 111 (1998).Google Scholar
16. Wan, J., Ling, Y., Sun, Q. and Wang, X., Phys. Rev. B 58, 10415 (1998).Google Scholar
17. Yeh, J. J. and Lindau, I., Atomic Data and Nuclear Data Tables, 32, 1 (1985).Google Scholar
18. Shirley, D. A., Phys. Rev. B 5, 4709 (1972).Google Scholar
19. Ley, L., in The Physics of Hydrogenated Amorphous Silicon II, ed. Joannopoulos, J. D. and Lucovsky, G. (Topics in Applied Physics 56, Springer-Verlag, Berlin, 1984) p. 61.Google Scholar
20. Lang, J. K., Baer, Y. and Cox, P. A., J. Phys. F 11, 121 (1981).Google Scholar