実験報告書様式（一般利用課題・成果公開利用）

MLF Experimental Report

提出日 Date of Report

課題番号 Project No.

装置責任者 Name of responsible person

2016A0307

Kenichi Oikawa

実験課題名 Title of experiment

装置名 Name of Instrument/（BL No.）

Structural and electrical characterization of neutron beam irradiated

NOBORU (BL10)

chalcogenide glass-silver structures and CBRAM devices

実施日 Date of Experiment

実験責任者名 Name of principal investigator

January 22-23, 2017

Yoshifumi Sakaguchi
所属 Affiliation
CROSS
試料、実験方法、利用の結果得られた主なデータ、考察、結論等を、記述して下さい。（適宜、図表添付のこと）
Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1. 試料 Name of sample(s) and chemical formula, or compositions including physical form.
Ag/ Ge20S80/ W/ SiO2/Si, Ag/ Ge40S60/ W/ SiO2/ Si, Ag/ Ge20Se80 W/ SiO2/Si, Ag/ Ge40Se60/ W/ SiO2/Si
Memory device (Ag/ Ge40Se60/ SiO2/ Si is inside)

2. 実験方法及び結果 （実験がうまくいかなかった場合、その理由を記述してください。）
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

We prepared 6 sample packages(Fig.1(a)) which are made ofaluminum coated polythene sheet(110mm x 110mm) and in which 4
different films (Fig.1(b)) and 1
memorydevice(Fig.1(c))

areFig.1 (a)Fig.1(b)Fig.1(c)contained. The exposure to light was avoided with thealuminum coated polythene sheet. The sample package
was set on the neutron beam path in order that all of thefilms and the device in the package were exposed to theneutron beam with 100mm x 100mm beam size. The
neutron beams were irradiated with 6 different time
conditions (1 min, 5 min, 20 min, 90 min, 6 h, and 22 h)
as summarized in Table 1. After cooling down of theradio-activation of the irradiated samples, the samples
were shipped to Boise State University (U.S.A.) and theeffect of the neutron irradiation was investigated byRaman spectrometer.
1Fig. 2

2. 実験方法及び結果（つづき） Experimental method and results (continued)
After receiving the samples in Boise their structure was studied by Raman

Irradiation time

spectroscopy. The spectra were fitted and the area under the peaks calculated.

1 min

In Ge20S80 and Ge40S60, the variation in the Dimerized S-S bondingwith the radiation follow the same trends. The double layer structure
remains constant with the radiation doses in the 40-60 composition.
The results for this system are shown in Figures 3(a) and 3(b).

5 min
20 min90 min6h

Ge20S80
Ge40S60

109

Demerized S-S bonding

Double Layer Structure

11876
540500

1000

1500

2000

50484644
42403836343230
2826242222 h

Ge20S80
Ge40S60

0Radiation Dose (Grad)

500

1000

Table 1

1500

2000

Radiation Dose (Grad)

Figure 3: Raman relative structural unit analysis due to neutron irradiation for GexS1-x film.
By deconvoluting the curve, the area under different structural unit are separated. The figure 4(a), 4(b),4(c) are demonstrating the structural unit changes with different radiation doses.
2344

Ge40Se60
Ge20Se80

42

22

20

19

5.5

38

CS/ES ratio

21Ge40Se60
Ge20Se80

6.0

40

Se-Se bonding

Eathane like bonding

Ge40Se60

3634
32

5.0
4.5
4.030

3.5

28

3.0

1805001000

1500

Radiation Dose (Grad)

2000

0500

1000

1500

2000

Radiation Dose (Grad)

0500

1000

1500

2000

Radiation Dose (Grad)

Figure 4: Raman relative structural unit analysis due to neutron irradiation for different compositionof GexSe1-x film.
From the above study, it is obvious that structural composition changes as the doses change. More structuralchanges are observed in Ge40Se60 possibly because of the presence of weak ethane-like structural units in thesefilms than Ge20Se80 films. Interestingly with increasing of the radiation dose the changes diminish, which wesuggest is due to the formation of a very high number of defects which are in a close proximity. This causes theirfast recombination and so the net effect is lack of structural change in the material. In case of silver diffusion it ismuch more expressed in the Ge20Se80 samples which could be related to the high affinity between the chalcogenelements and Ag on one hand and on the other hand to the formation of defects mainly related to the lone-pairelectrons of the chalcogen elements which due to their negative charge attract the Ag ions.

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