| Project/Area Number |
07555097
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
Electronic materials/Electric materials
|
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
KAWABE Mitsuo University of Tsukuba, Institute of Materials Science, Professor, 物質光学系, 教授 (80029446)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
OKADA Yoshitaka University of Tsukuba, Institute of Materials Science, Assistant Professor, 物質光学系, 講師 (40224034)
|
|---|
| Project Period (FY) |
1995 – 1997
|
| Project Status |
Completed (Fiscal Year 1997)
|
| Budget Amount *help |
¥17,900,000 (Direct Cost: ¥17,900,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 1995: ¥12,300,000 (Direct Cost: ¥12,300,000)
|
|---|
| Keywords | Heteroepitaxy / Surfactant effects / Growth of GaAs-on-Si, Ge / Defects, dislocations / Molecular beam epitaxy / Atomic H-assisted epitaxy / Deep levels / High-efficiency solar cells / 結晶欠陥、転位 / 量子構造太陽電池 / 表面修飾 / 相互拡散 / GaAs / Si / Ge / 水素原子 / ヘテロエピタキシ |
|---|
| Research Abstract |
Realization of high-efficiency solar cells requires high-quality heteroepitaxial growth techniques. There are a number of issues, which need to be technically solved even in the growth of GaAs-on-Si, one of the most promising and intensely studied materials for this application. We have studied the effects of atomic hydrogen being irradiated to substrate during cleaning and in growth by molecular beam epitaxy (MBE). It is found that atomic H plays very important roles as a surfactant such that the heteroepitaxial growth proceeds by a two-dimensional layr-by-layr mode as opposed to islanded growth as seen in most lattice-mismatched heteroepitaxy. The consequence of such favored growth mode in low-temperature epitaxy is drastic reduction of threading dislocation densities in GaAs-on-Si. We have also investigated the effects of atomic H on passivation of defects and deep level electronic traps and minority carrier lifetimes, which are important material parameters in assessing the performance of solar cells. In all of the test solar cells fabricated, those grown by atomic H-assisted MBE have shown better and improved photovoltaic response than those grown by the conventional MBE with rest of the growth conditions being the same.
|
