Skip to main content Accessibility help

Nmr Study of Ortho-Molecular Hydrogen in Hydrogenated Amorphous Silicon

  • Tining Su (a1), P.C. Taylor (a1), Shenlin Chen (a1), R.S. Crandall (a2) and A.H. Mahan (a2)...


A Jeener-Broekaert three-pulse sequence is used to investigate ortho-molecular hydrogen (o-H2) in device quality amorphous silicon films prepared by plasma enhanced chemical vapor deposition (PECVD) and hot wire CVD (HWCVD). For the PECVD sample, the concentration of hydrogen molecules is ~ 11% of the total hydrogen concentration, one order of magnitude larger than that inferred from spin-lattice relaxation time measurements (~1%). Hence, most of the hydrogen molecules do not serve as effective relaxation centers. For HWCVD samples with ~3 to 4% hydrogen and very low void densities, the concentrations of hydrogen molecules are ~1% of the total hydrogen concentration. In these samples, spin-lattice relaxation measurements for bonded hydrogen indicate that the concentration of hydrogen molecules that contribute to spin-lattice relaxation is at most 0.1% of the total hydrogen concentration. Spin-lattice relaxation time (T1) measurements of ortho-molecular hydrogen indicate two very different T1's. The longer T1 is ~ 0.6 s, possibly due to an electric quadrupole-quadrupole (EQQ) interaction between o-H2 molecules and, the shorter T1 is ~ 3 ms, very close to that calculated for a two-phonon Raman process for rotating o-H2.



Hide All
1. Boyce, J. B., and Stutzmann, M., Phys. Rev. Lett. 54, 562 (1985).
2. Carlos, W. E. and Taylor, P. C., Phys. Rev. B 25, 1435 (1982).
3. Chan, P. H., Ph.D. Thesis, Washington University, September, 1993 (unpublished).
4. Conradi, M. S., Luszczynski, K., and Norberg, R. E., Phys. Rev. B 20, 2594 (1979).
5. Conradi, M. S. and Norberg, R. E., Phys. Rev. B 24 2285 (1981).
6. Drabold, D. A. and Fedders, P. A., Phys. Rev. B 39, 6325 (1989).
7. Fedders, P. A., Phys. Rev. B, 20, 2588 (1979).
8. Fedders, P. A., Fisch, R., and Norberg, R. E., Phys. Rev. B 31, 6887 (1985).
9. Jeener, J. and Broekaert, P., Phys. Rev., 157, 232 (1967).
10. Liu, Xiao, White, B. E. Jr, and Pohl, R. O., Phys. Rev. Lett. 78, 4418 (1997).
11. Norberg, R. E., Leopold, D. J., Fedders, P. A., J. Non-cryst. Solids, 227–230, 124 (1998).
12. Reif, F. and Purcell, E. M., Phys. Rev. 91, 631 (1953).
13. Silvera, I. F., Rev. Mod. Phys. 52, 393 (1980).
14. Hari, P., Taylor, P.C. and Street, R.A., J. Non-Cryst. Solids 198–200, 736 (1996), and references contained therein.


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed