| Numéro |
J. Phys. Colloques
Volume 42, Numéro C4, Octobre 1981
Proceedings of the Ninth International Conference on Amorphous and Liquid Semiconductors
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| Page(s) | C4-455 - C4-458 | |
| DOI | https://doi.org/10.1051/jphyscol:1981495 | |
J. Phys. Colloques 42 (1981) C4-455-C4-458
DOI: 10.1051/jphyscol:1981495
DENSITY OF STATES STUDY IN SPUTTERED a-Si : H : EFFECT OF IMPURITIES AND H RELATED DEFECTS
P. Viktorovitch1, G. Moddel2, J. Blake2, S. Oguz2, R.L. Weisfield2 and W. Paul21 École Centrale de Lyon, ERA CNRS Génie Électronique (no. 661), 36 Route de Dardilly, 69130 Ecully, France.
2 Division of Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, U.S.A.
Abstract
We observe two regimes in the variation of gap size (E04) and density of states (DOS) as a function of H-content (cH) in sputtered a-Si : H. In the first regime, an increase in cH from 5 to 17% is accompanied by an exponential functional decrease of the DOS near midgap, which varies also directly with E04 over a wide range of preparation conditions. In the second regime, additional incorporation of H beyond 17% fails to further decrease the DOS (with cH and E04), which shows a saturation with scatter. This behavior is interpreted in terms of H-induced and residual impurity related defects. Variation of the DOS in the lower half of the gap, responsible for hole trapping, is observed via the hole mobility-lifetime product, which exhibits a dramatic drop with impurity incorporation (P, O) and deteriorates for increasing cH in the second regime.