Atomic-scale study on electronic structure and emission mechanism or GaN-related semi-conductor quantum dots

GaN相关半导体量子点的电子结构和发射机制的原子尺度研究

• 批准号: 10650001
• 负责人: SAITO Toshio
• 金额: $ 1.34万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650001/
• 关键词: nitride semiconductors; gallium nitride; indium gallium nitride; quantum dot; electronic structure; tight-binding method; valence-force-field method; quantum confinement; 窒化インジウム; 混晶; 量子閉じ込め効果

The atomic and electronic structures of InィイD2xィエD2GaィイD21-xィエD2N hexagonal quantum dots (QDs) have been calculated theoretically. A valence-force-field method is used for the calculation of the atomic positions and strain energy in the InィイD2xィエD2GaィイD21-xィエD2N random alloy. We analyzed the bond-length and bond-angle distribution in the alloy due to the "alloy disorder." The calculated change in the average Ga-N and In-N bond lengths vs. x is in good agreement with the recent experimental data. The alloy phase stability is studied based on the calculated strain energy. An spィイD13ィエD1 tight-binding method is used for the calculation of the electronic structure of the free-standing and GaAs-embedded QDs. The energy gap, energy levels, and wavefunctions are calculated accurately as a function of the QD size. For the InィイD20.2ィエD2GaィイD20.8ィエD2N QD embedded in the GaN barrier (dot diameter 86.4 Å, dot height 20.8 Å, GaN barrier thickness 21 Å), we calculated the energies of electron and hole levels (C1-C3 and V1-V3, respectively) near the energy gap. We found that the three hole levels (V1-V3) are closely spaced, while the electron levels are the ground state (C1) and the closely spaced excited states (C2 and C3). The gap value EィイD2gィエD2(C1-V1) is calculated to be 2.715 eV. The electron wavefunction is almost completely confined in the QD inside, while exhibiting atomic scale fluctuation due the "alloy disorder."

的原子和电子结构在ィイD2xィエD2GaィイD21-xィエD2N六角量子点(量子点)从理论上计算。价力场方法用于计算原子位置和应变能的ィイD2xィエD2GaィイD21-xィエD2N随机合金。分析了由于“合金无序”导致的合金中的键长和键角分布。计算出的Ga-N和in - n平均键长随x的变化与最近的实验数据吻合得很好。在计算应变能的基础上研究了合金的相稳定性。采用sp . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ . γ。能隙、能级和波函数作为量子点大小的函数精确地计算出来。对于嵌入GaN势垒中的In γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。我们发现三个空穴能级（V1-V3）是紧密间隔的，而电子能级是基态（C1）和激发态（C2和C3）。计算得到的间隙值为E°c . D2g°c . D2(C1-V1) = 2.715 eV。电子波函数几乎完全被限制在量子点内部，同时由于“合金无序”而表现出原子尺度的波动。

项目成果

T. Saito: "Atomic structure and phase stability of In_xGa_<1-x>N random alloys calculated using a valence-force-field method"Physical Review B. 60・3. 1701-1706 (1999)

T. Saito：“使用价力场法计算的In_xGa_<1-x>N随机合金的原子结构和相稳定性”Physical Review B. 60・3（1999）

T. Saito: "Theoretical calculations for atomic and electronic structures of InGaN quantum dots"Proc. of 4th Symp. on Atomic-Scale Surface and Interface Dynamics (Tsukuba, Japan, 2000). 75-80 (2000)

T. Saito：“InGaN 量子点原子和电子结构的理论计算”Proc。

T. Saito, J. N. Schulman, and Y. Arakawa: "(Strain-energy distribution and electronic structure of InAs pyramidal quantum dots with uncovered surfaces : Tight-binding analysis"Physical Review B. 57. 13016 (1998)

T. Saito、J. N. Schulman 和 Y. Arakawa：“（具有未覆盖表面的 InAs 金字塔量子点的应变能量分布和电子结构：紧束缚分析”物理评论 B. 57. 13016 (1998)

T. Saito, T. Someya, K. Tachibana, S. Ishida, O. Moriwaki, and Y. Arakawa: "Formation of InGaN Quantum Dots : MOCVD Growth and Electronic Structures"Proc. of 3rd SANKEN Int. Symp. on Advanced Nanoelectronics : Devices, Materials, and Computing, Osaka, Jap

T. Saito、T. Someya、K. Tachibana、S. Ishida、O. Moriwaki 和 Y. Arakawa：“InGaN 量子点的形成：MOCVD 生长和电子结构”Proc。

T. Saito: "Theoretical calculations for atomic and electronic structures of InGaN quantum dots"Proceedings of the Fourth Symposium on Atomic-Scale Surface and Interface Dynamics. 75-80 (2000)

T. Saito：“InGaN量子点原子和电子结构的理论计算”第四届原子尺度表面和界面动力学研讨会论文集。