| Budget Amount *help |
¥24,570,000 (Direct Cost: ¥18,900,000、Indirect Cost: ¥5,670,000)
Fiscal Year 2017: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
Fiscal Year 2016: ¥8,450,000 (Direct Cost: ¥6,500,000、Indirect Cost: ¥1,950,000)
Fiscal Year 2015: ¥9,620,000 (Direct Cost: ¥7,400,000、Indirect Cost: ¥2,220,000)
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| Outline of Final Research Achievements |
The purpose of this research is to expand the bandgap of BaSi2 by doping with carbon (C). We used propane as a C source, and formed C-doped BaSi2 films. Regardless of imput RF power, the C concentration in the grown films was on the order of 10~21 cm-3 and the a-axis lattice constant remained the same. We ascribed this result to the presence of vacancies in the BaSi2 lattice.We had set the Ba to Si deposition rate ratio (γ) at 3.0 from the fact that the full width at half maximum of x-ray diffraction peak intensity reached a minimunm at γ=3.0. We varied it from 1.0 to 5.1 and measured the photoresponse spectra and carrier cocentration of the films. It was found that the photoresponsivity was so sensitive to γ thereby the presence of vacancies. It reached a maximum at γ = 2.2. The carrier concentration decreased down to 10^15 cm-3. Therefore it is very important to controlγ precisely to decrease the number of vacancies to achieve wide bandgap Ba(Si,C)2 films.
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