| Project/Area Number |
12650325
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Electronic materials/Electric materials
|
|---|
| Research Institution | TOKYO INSTITUTE OF POLYTECHNICS |
|---|
Principal Investigator |
AOKI Takeshi TOKYO INSTITUTE OF POLYTECHNICS, Faculty of Engineering, Professor, 工学部, 教授 (10023186)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Shi-ichi TOKYO INSTITUTE OF POLYTECHNICS, Faculty of Engineering, Research Associate, 工学部, 助手 (60277944)
|
|---|
| Project Period (FY) |
2000 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
|
|---|
| Keywords | nanocrystal / amorphous / microcrystal / photoluminescence / lifetime / Germanium / CVD / ECR Plasma / エピタキシャル / 励起子 / 優先配向 / ECR |
|---|
| Research Abstract |
Hydrogenated microcrystalline germanium (μc-Ge : H) films were deposited on crystalline (c-) Si, c-Ge and glass substrates by electron-cyclotron-resonance plasma chemical vapor deposition (ECRPCVD). With increasing substrate temperature (Ts), an amorphous to microcrystalline phase transition started at Ts 【approximately equal】 50 ℃. Above 200 ℃, the crystalline volume fraction (_<Xc>) on the c-Si and Ge substrates exceeded 【approximately equal】 80% and preferential growth of μc-Ge : H along crystallographic axes of the substrates was observed. For the glass substrates, _<Xc> was a maximum at 【approximately equal】 155 ℃, above which it decreased with increasing T_s. Hydrogen desorption from the growth surface is probably responsible for suppressing microciystalline nucleation. The PL peak energy and magnitude decreased with increasing T_s, but PL spectrum even at T_s = 313 ℃ being broad compared with that of c-Ge suggest the PL arises from the amorphous part of the grain boundary.
High-quality hydrogenated amorphous germanium (a-Ge : H) films were deposited under the critical condition of the film growth of amorphous-crystalline phase transition. Double-peak lifetime distribution were observed in a-Ge : H. A dual-phase double lock-in (DPDL) quadrature frequency resolved spectroscopy (QFRS) developed to measure ns lifetime with a newly devised semi-analytical deconvolution revealed that the PL lifetime distribution is basically double-peaked in chalcogenide as well as tetrahedral semiconductors such as a-Si : H and a-Ge : H. The short lived (ns-μs) and the long lived (ms) components are attributed singlet and triplet excitons, respectively. We proposed that controlling spin states of electron-hole pairs is a key to prolong the recombination lifetime and improve the device-quality e.g. efficiency of solar cells.
|
