| 1.Research Institution | Ritsumeikan University | |
| 2.University-Industry Cooperative Research Committee | 147th Committee on Amorphous and Nano-Crystalline Materials | |
| 3.Term of Project | FY1996〜FY2000 | |
| 4.Project Number | 96R14701 | |
| 5.Title of Project | Physics of Nanocrystalline Semiconductors and their Application to New Functional Devices |
| Name | Institution,Department | Title of Position |
| Yoshihiro Hamakawa | Ritsumeikan University | Professor |
7.Core Members
| Names | Institution,Department | Title of Position |
| Hiroaki Okamoto | Osaka University | Professor |
| Masataka Hirose | Hiroshima University | Professor |
| Hideyuki Takakura | Ritsumeikan University | Professor |
8.Cooperating Researchers
| Names | Institution,Department | Title of Position |
| Fumiko Yonezawa | Keio University | Professor |
| Shoji Nitta | Gifu University | Professor |
| Seiichi Miyazaki | Hiroshima University | Associate Professor |
9.Summary of Research Results
|
A series of investigations on physics of nano-crystalline semiconductors and their application to new functional devices have been made. Results are summarized as following: 1) On the fabrication technologies of nano-crystalline silicon, optimum deposition conditions for the best quality of the film are identified and their electrical and opto-electronic properties are characterized. 2) With the detailed parameter control in the initial deposition, homogeneous semispherical nc-Si dots were fabricated successfully. Result of PL spectra measurements are explained by the theory of quantum dot model. 3) Observed EL emission has two distinguished structures centered at 1.3eV and 1.6eV. In the higher energy side structure, one can see dark red visible light due to the broad band emission. 4) On the basis of these experimental results, an attempt has been made on the higher energy gap nanocrystal materials. We have succeeded a strong red light emission from nc-ZnS:Mn. 5) With the tight-binding-approximation, electronic band structure and the electronic density of state in nc-Si are calculated firstly. It has been shown that experimentally observed light emission could be explained by the deviation of the crystal symmetry including bond length and tilt angles in the system. 6) Utilizing the excellent photoconductive and electrical properties in the nc-Si, high efficiency low cost a-Si//nc-Si tandem type solar cells are proposed and both experimentally and theoretically verified. |
10.Key Words
(1)nanocrystalline semiconductor、(2)amorphous silicon、(3)valency control
(4)band gap energy control、(5)self-assembling、(6)quantum dot
(7)thin film light emitting device、(8)tandem type solar cell、(9)OEIC
11.References
| Author | Title of Article | |||
| J. Koga, K. Nishio, H. Ohtani, T. Yamaguchi, and F. Yonezawa | Electronic Properties of Low Dimensional Si Nanostructure, I. Local Electronic Probabilities | |||
| Journal | Volume | Year | Pages Concerned | |
| J. Phys. Soc. Jpn. | 69 | 2000 | 2188 | |
| Author | Title of Article | |||
| S. Miyazaki, K. Shiba, N. Miyoshi, K. Etoh, A. Kohno and M. Hirose | Luminescence Study of Self-Assembled Silicon Quantum Dots | |||
| Journal | Volume | Year | Pages Concerned | |
| Mat. Res. Soc. Symp. Proc. | 536 | 1999 | 45-50 | |
| Author | Title of Article | |||
| S. Nonomura, T. Gotoh, M. Nishio, T. Sakamoto, M. Kondo | Photoinduced Expansion in Hydrogenated Amorphous Silicon | |||
| Journal | Volume | Year | Pages Concerned | |
| Mat. Res. Soc. Symp. Proc. | 577 | 1999 | 337-345 | |
| Author | Title of Article | |||
| T. Toyama, Y. Kotani, H. Okamoto, and H. Kida | Light Emission from Nanocrystalline Si Thin-Film Light Emitting Diodes due to Tunneling Carrier Injection | |||
| Journal | Volume | Year | Pages Concerned | |
| Appl. Phys. Lett. | 72 | 1999 | 1489-1491 | |
| Author | Title of Article | |||
| Y. Hamakawa and H. Takakura | Key issues for the efficiency improvement of silicon basis stacked solar cells | |||
| Journal | Volume | Year | Pages Concerned | |
| Conf. Record 28th IEEE PV Spec. Conf. | 2000 | 766-771 | ||
| Author | Title of Book | ||
| Shoji Nitta et al. | Sample Fabrication Technologies -Amorphous Materials- | ||
| Publisher | Year | Pages | |
| Maruzen Pub. Co. | 2000 | 302 | |
| Author | Title of Book | ||
| Y. Hamkawa, H. Okamoto, H. Takakura et al. | Solar PV Power Generation -Recent Technologies and Systems- | ||
| Publisher | Year | Pages | |
| CMC | 2000 | 318 | |
| Author | Title of Book | ||
| H. Okamoto, H. Takakura et al. | Fundamentals and Application of Thin Film Solar Cells | ||
| Publisher | Year | Pages | |
| OHM-Sha Pub. Co. | 2001 | 265 | |