1998 Fiscal Year Final Research Report Summary
CONTRIBUTION OF FLOATING BONDS TO LIGHT-INDUCED DEGRADATION OF HYDROGENATED AMORPHOUS SILICON
| Project/Area Number |
09650010
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Kanazawa University |
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Principal Investigator |
KUMEDA Minoru Kanazawa Univ., Fac.of Eng., Professor, 工学部, 教授 (30019773)
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| Co-Investigator(Kenkyū-buntansha) |
MORIMOTO Akiharu Kanazawa Univ., Fac.of Eng., Associate Professor, 工学部, 助教授 (60143880)
SHIMIZU Tatsuo Kanazawa Univ., Fac.of Eng., Professor, 工学部, 教授 (30019715)
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| Project Period (FY) |
1997 – 1998
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| Keywords | hydrogenated amorphous silicon / light-induced degradation / dangling bonds / floating bonds / randomness / electron spin resonance / light-induced electron spin resonance / spin-lattice relaxation time |
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| Research Abstract |
Relation between the randomeness of amorphous network and the creation of defects was first investigated in an amorphous system of a-Ge_<1-x> C_x : H films which contains constituent atoms with largely different covalent radii, and compared the results with those in a-Ge_<1-x>Si_x, : H films which contains constituent atoms with close covalent radii. It. was found that the addition of C atoms makes the films stricture more random and increase the Ge dangling bonds per Ge atoms.
Next we measured the spin-lattice relaxation time T_1 of Si dangling bonds and its dependence on the light-soaking time in a-Si : H.It was found that T_1 has a fairly good correlation with the randomness of the amorphous network estimated from the Urbach energy. It was also found that T_1's for the broad and narrow component signals of the light-induced ESR decreases by light-soaking, in contrast to that for the dark component. This might be an important clue to judge whether the origin of the broad component of the light-induced ESR comes from the floating bonds.
Finally we tried to explain the defect creation processes by the light-soaking and electron-beam irradiation, using rate equations based on a model in which the floating bonds contribute to create dangling bonds.
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