抄録
In xGa 1-xN multiple-quantum-well laser diode structure, which lased at 405 nm, was shown to have atomically-flat interfaces between each layer. Nanometer-probe compositional analysis showed that InN mole fraction, x, in the wells and barriers are approximately 6 % and 2 %, respectively, which agreed with the result obtained from high-resolution x-ray diffraction measurement. The Stokes-like shift (SS) at 300 K was 49 meV, being approximately 65 % of the luminescence linewidth. The localization depth, E 0, of quantum-well (QW) excitons as estimated to be 35 meV at 300 K though the compositional fluctuation in the well was as small as 1 % or less (detection limit) within adjacent 20-30 nm lateral length scale. Since the well thickness fluctuation is insufficient to reproduce SS or E 0, effective bandgap inhomogeneity is attributed to be due to large bandgap bowing in InGaN. The spontaneous emission was thus assigned as being due to the recombination of QW excitons weakly localized in exponential tail-type potential minima in the QW. The size of localization is smaller than the quantum-disk [M. Sugawara, Phys. Rev. B 51, 10743 (1995)]-size. Such small bandgap inhomogeneity can be leveled by injecting high density carriers under lasing conditions, which can explain the general experimental finding that the quantum efficiency decreases with increasing carrier density in InGaN QW devices due to free carrier trapping into threading dislocations.
| 元の言語 | English |
|---|---|
| ホスト出版物のタイトル | Materials Research Society Symposium - Proceedings |
| 編集者 | C Wetzel, M Shur, U Mishra, B Gil, K Kishino |
| 巻 | 639 |
| 出版物ステータス | Published - 2001 |
| 外部発表 | Yes |
| イベント | GaN and Related Alloys 2000 - Boston, MA, United States 継続期間: 2000 11 27 → 2000 12 1 |
Other
| Other | GaN and Related Alloys 2000 |
|---|---|
| 国 | United States |
| 市 | Boston, MA |
| 期間 | 00/11/27 → 00/12/1 |
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
これを引用
Role of localized quantum well excitons in InGaN quantum well structure correlated with microstructural analysis. / Chichibu, S. F.; Sota, Takayuki; Nakamura, S.
Materials Research Society Symposium - Proceedings. 版 / C Wetzel; M Shur; U Mishra; B Gil; K Kishino. 巻 639 2001.研究成果: Conference contribution
}
TY - GEN
T1 - Role of localized quantum well excitons in InGaN quantum well structure correlated with microstructural analysis
AU - Chichibu, S. F.
AU - Sota, Takayuki
AU - Nakamura, S.
PY - 2001
Y1 - 2001
N2 - In xGa 1-xN multiple-quantum-well laser diode structure, which lased at 405 nm, was shown to have atomically-flat interfaces between each layer. Nanometer-probe compositional analysis showed that InN mole fraction, x, in the wells and barriers are approximately 6 % and 2 %, respectively, which agreed with the result obtained from high-resolution x-ray diffraction measurement. The Stokes-like shift (SS) at 300 K was 49 meV, being approximately 65 % of the luminescence linewidth. The localization depth, E 0, of quantum-well (QW) excitons as estimated to be 35 meV at 300 K though the compositional fluctuation in the well was as small as 1 % or less (detection limit) within adjacent 20-30 nm lateral length scale. Since the well thickness fluctuation is insufficient to reproduce SS or E 0, effective bandgap inhomogeneity is attributed to be due to large bandgap bowing in InGaN. The spontaneous emission was thus assigned as being due to the recombination of QW excitons weakly localized in exponential tail-type potential minima in the QW. The size of localization is smaller than the quantum-disk [M. Sugawara, Phys. Rev. B 51, 10743 (1995)]-size. Such small bandgap inhomogeneity can be leveled by injecting high density carriers under lasing conditions, which can explain the general experimental finding that the quantum efficiency decreases with increasing carrier density in InGaN QW devices due to free carrier trapping into threading dislocations.
AB - In xGa 1-xN multiple-quantum-well laser diode structure, which lased at 405 nm, was shown to have atomically-flat interfaces between each layer. Nanometer-probe compositional analysis showed that InN mole fraction, x, in the wells and barriers are approximately 6 % and 2 %, respectively, which agreed with the result obtained from high-resolution x-ray diffraction measurement. The Stokes-like shift (SS) at 300 K was 49 meV, being approximately 65 % of the luminescence linewidth. The localization depth, E 0, of quantum-well (QW) excitons as estimated to be 35 meV at 300 K though the compositional fluctuation in the well was as small as 1 % or less (detection limit) within adjacent 20-30 nm lateral length scale. Since the well thickness fluctuation is insufficient to reproduce SS or E 0, effective bandgap inhomogeneity is attributed to be due to large bandgap bowing in InGaN. The spontaneous emission was thus assigned as being due to the recombination of QW excitons weakly localized in exponential tail-type potential minima in the QW. The size of localization is smaller than the quantum-disk [M. Sugawara, Phys. Rev. B 51, 10743 (1995)]-size. Such small bandgap inhomogeneity can be leveled by injecting high density carriers under lasing conditions, which can explain the general experimental finding that the quantum efficiency decreases with increasing carrier density in InGaN QW devices due to free carrier trapping into threading dislocations.
UR - http://www.scopus.com/inward/record.url?scp=0035557614&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035557614&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:0035557614
VL - 639
BT - Materials Research Society Symposium - Proceedings
A2 - Wetzel, C
A2 - Shur, M
A2 - Mishra, U
A2 - Gil, B
A2 - Kishino, K
ER -