利用有效质量方法和变分原理,考虑内建电场效应和量子点的三维约束效应,研究了约束在GaN/AlxGa1-xN圆柱形量子点中的激子特性与量子点的结构参数以及势垒层中Al含量之间的关系.结果表明:对给定大小的量子点,随其高度的增加激子结合能出现一最大值,此时载流子被最有效的约束在量子点内;内建电场使量子点的有效带隙减小,电子、空穴产生明显分离,从而影响量子点的光学性质.理论计算的光跃迁能和实验结果一致.
Within the framework of effective-mass approximation, the exciton states confined in GaN cylindrical quantum dots (QDs) were investigated by means of a variational approach. The relationship between exciton states and the structural parameters of the QDs was studied in detail. The numerical results show that the exciton binding energy is sensitive to the shape of the QD for a definite volume. There is a maximum in the binding energy, where the electrons and holes are the most efficiently confined in the QDs. The built-in electric field (BEF) leads to a remarkable reduction of the QD effective band gap and an apparent electron-hole spatial separation. The QDs optical properties are thus greatly affected by the BEF. Our calculated optical transition energies are in good agreement with experimental data.
参考文献
| [1] | Widmann F.;Feuillet G.;Samson Y.;Rouviere JL.;Pelekanos N.;Daudin B. .Growth kinetics and optical properties of self-organized GaN quantum dots[J].Journal of Applied Physics,1998(12):7618-7624. |
| [2] | Widmann F;Simon J;Daudin B et al.[J].Physical Review B,1998,58(24):R15989. |
| [3] | Ramvall P.;Nomura S.;Riblet P.;Aoyagi Y.;Tanaka S. .Observation of confinement-dependent exciton binding energy of GaN quantum dots[J].Applied physics letters,1998(8):1104-1106. |
| [4] | Ramvall P;Riblet P;Nomura S et al.[J].Journal of Applied Physics,2000,87(08):3883. |
| [5] | Tanaka S;Lee J S;Ramvall P et al.[J].Japanese Journal of Applied Physics,2003,42(8A):L885. |
| [6] | Tanaka S;Iwai S;Aoyagi Y .[J].Applied Physics Letters,1996,69(26):4096. |
| [7] | Tanaka S;Hirayama H;Aoyagi Y;Narukawa Y;Kawakami Y;Fujita S;Fujita S .Stimulated emission from optically pumped GaN quantum dots[J].Applied physics letters,1997(10):1299-1301. |
| [8] | Fonoberov V A;Balandin A A .[J].Journal of Applied Physics,2003,94(11):7178. |
| [9] | Fonoberov V A;Pokatilov E P;Balandin A A .[J].Journal of Nanoscience and Nanotechnology,2003,3(03):253. |
| [10] | Andreev AD.;O'Reilly EP. .Theory of the electronic structure of GaN/AIN hexagonal quantum dots[J].Physical Review.B.Condensed Matter,2000(23):15851-15870. |
| [11] | Oberhuber R.;Vogl P.;Zandler G. .Mobility of two-dimensional electrons in AlGaN/GaN modulation-doped field-effect transistors[J].Applied physics letters,1998(6):818-820. |
| [12] | Leroux M.;Massies J.;Gil B.;Lefebvre P.;Bigenwald P.;Grandjean N. .Barrier-width dependence of group-III nitrides quantum-well transition energies[J].Physical Review.B.Condensed Matter,1999(3):1496-1499. |
| [13] | Bernardini F.;Vanderbilt D.;Fiorentini V. .SPONTANEOUS POLARIZATION AND PIEZOELECTRIC CONSTANTS OF III-V NITRIDES[J].Physical Review.B.Condensed Matter,1997(16):10024-10027. |
| [14] | Goff S L;Stébé B .[J].Physical Review B,1993,47(03):1383. |
| [15] | Szafran B;Bednarek S;Adamowski J .[J].Physical Review B,2001,64(12):125301. |
| [16] | 戴宪起,黄凤珍,郑冬梅.Al含量对GaN/Alx Ga1-x N量子点中激子态的影响[J].半导体学报,2005(04):697-701. |
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