1990 Fiscal Year Final Research Report Summary
Chemical reaction and structural change induced by irradiation of light or electron beam at surface of chalcogenide films containing a large quantity of Ag
| Project/Area Number |
01460075
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Nagoya Institute of Technology |
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Principal Investigator |
MARUNO Shigeo Nagoya Inst. Tech. Engineering Professor, 工学部, 教授 (60024204)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAGUCHI Takeshi Nagoya Inst. Tech. Engineering Res. Asso., 工学部, 助手 (80144195)
DOI Akira Nagoya Inst. Tech. Engineering Asso. Prof., 工学部, 助教授 (30024326)
MASUI Kanji Nagoya Inst. Tech. Engineering Asso. Prof., 工学部, 助教授 (10024358)
SAJI Manabu Nagoya Inst. Tech. Engineering Professor, 工学部, 教授 (50024211)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Photosurface deposition / Photodoping / Super ionic conduction / Electron Beam Surface deposition / Chalcogenide glass / Amorphous film |
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| Research Abstract |
A new type optical memory device with high resolving power and high contrast image has been made by (Ge_<0.3>S_<0.7>)_<100-X>Ag_X amorphous film containing a large quantity of Ag. The memory dots are formed by a great number of fine silver particles precipitated by the metal photosurface deposition (PSD) phenomenon on the film. The PSD mechanism has been discussed on the basis of the characteristics of phenomenon and the film structure. The PSD properties such as photosensitivity resolving power stability, etc.have been also examined from the point of view of the practical application to the memory device. In summary, the results are as follows ; (1) The PSD sensitivity becomes maximum in the range of 65*x*67 and the addition of a small amount of Au (1-2 wt%) yielded a pronounced effect on the sensitivity. (2) The PSD pattern can be erased by annealing below T_g of film but the formation of Ag_8GeS_6 crystal and the photo-oxidation a the film surface causes the deterioration of device.
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(3) A marked structural change is induced by the irradiation of electron beam and the pattern as high quality as PSD can be written by the electron beam. (4) The PSD film is a super ionic conducter of Ag^+ (greater than 10^<-3>S/cm at 20^ﾟC). ITO/film/Au sandwich cell showed the conversion efficiency of 10^<-2>% and the open circuit photovoltage of 0.5 V. (5) The structural studies by ESCA. FT-IR and X-ray diffraction suggest that the phase separation of Ag_<poor> (Ge(4)-S(2) network structure of Argyrodite Ag_8GeS_6) and Ag_<rich> (Ge(6)-S(6) network structure of GeS) occurs at the range x*40 and the silver particles precipitate on the Ag_<rich> phase by light illumination. The similar result has been obtained for (Ge_<0.3>Se_<0.7>)_<100-x>Ag_x system in which the phase separation and the PSD are observed at x*30 and x*40. respectively. (6) The Ag^+ ions in the film diffuse toward the surface and accumulate around the illuminated region, since the electrical potential of the illuminated region is negative. The Ag^+ ions joint to the electron supplied by the neucleous of Ag deposits (Ag^+ + e -> metallic Ag), leading to the formation of metallic Ag disk deposit. Less
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Research Products
(6 results)
