异质结能带边不连续性的第一性原理计算

【中文摘要】 本文根据异质结界面两侧的平均键能相互“对齐”的研究结果,以平均键能作为参考能级,采用改进计算效率的LMTO-ASA能带从头计算方法,计算了10种异质结的价带边不连续ΔE_v值,所得结果与更严格的第一性原理的界面自洽计算的结果非常一致,而且计算量比界面自洽方法要小得多,便于在中型计算机条件下推广应用.国家和福建省自然科学基

Theoretical Calculation of B arrier Height of Metal-semiconductor Contacts

【中文文摘】采用平均键能作为参考能级计算了十种金属 -半导体接触势垒高度 ,其计算结果与实验值的符合程度不亚于 Tersoff和 M o¨ nch所采用的电中性能级方法 ,计算结果表明平均键能方法和 Tersoff提出的电中性能级方法一样 ,可作为金属 -半导体接触势垒高度的一种理论计算方法 【英文文摘】Taken the average -bond-energy as the reference level,ten barrier heights of metal-semiconductor c ontacts are calculated.The coincident de gree of our calculational values and exp erimental values is not less than that o f charge-neutrality point method,adopted by Tersoff and M o¨ nc h.It shows that the average-bond-energy method,similar to Tersoff's charge-neutr ality point method,can be used as one of the methods in theoretical calculation of metal-semiconductor contacts.厦门大学校级自选课题 (Y0 70 10 )资

Electronic Structure of Strained layer Superlattice GaN AlN

采用有效质量理论6带模型，计算了应变层超晶格gAnAln（001）的电子结构，具体计算不同应变状态的价带子能带色散曲线、光吸收曲线。分析了应变状态以及重轻空穴和自旋轨道分裂带相互作用对子带结构的影响。The electronic structure of strained layer superlattice GaN AlN(001) has been studied within framework of the 6 band Luttinger model in the effective mass theory. The valence band structure and the absorption spectra for different strain conditions are calculated. The effects of strain and coupling among heavy hole, light hole, and spin split off bands on valence band structure are discussed.福建省自然科学基金;厦门光电子工业部资

The Static Properties of AlN and GaN,and the Valence-band ofFsets of AlN/GaN Heterojunction

采用lMTO能带从头计算方法，计算了闪锌矿（立方）结构AIn和gAn的静态性质；用平均键能方法，预言了Aln与gAn自由应变生长、以Aln为衬底和以gAn为衬底等三种不同应变状态下Aln/gAn应变层异质结的△EV值；最后，采用超原胞（AIn）n（gAn）n（001），（n=1，3，5）界面自洽计算方法，考察了超晶格中平均键能EM的“对齐”程度和验证了价带偏移△EV计算结果的准确性。The static properties of cubic AlN and GaN (zinc-blende structure) are calculated by ab initio LMTO method.Using average bonding energy method,the valence-band ofFsets of AlN/GaN strained layer heterojunction under three strained conditions (i.e.growing GaN layer on substrate of AlN,growing AlN layer on substrate of GaN,and AlN and GaN strained Freely to Form the hetero-junction) are predicted.Finally, the calculated results of valence-band ofFsets △Ev and the "alignment" of average bonding energy Em in strained layer superlattice (AlN )n (GaN)n (001), (n = 1,3, 5) are veriFied by supercell selF-consistent calculation.福建省自然科学基

Calculation of Optical Properties of Zinc blende GaN,AlN and Their Alloys Ga 1 x Al x N

闪锌矿结构gAn、Aln和合金gA1-XAlXn光学性质计算何国敏王仁智郑永梅（厦门大学物理学系厦门361005）随着人们对发光二极管和半导体激光器等光电器件的深入研究，工作于蓝紫波段的半导体材料受到普遍的重视.宽带隙半导体gAn和Aln正是目前蓝紫...The nonlocal empirical pseudopotential method has been used to calculate the electronic structure of GaN, AlN and their alloys Ga 1 x Al x N .The imaginary part of the dielectric function of alloys Ga 1 x Al x N is also calculated with the virtual crystal approximation,and its trend versus Al fraction x are also discussed.国家和福建省自然科学基金;厦门大学光电子公司工业部资

Hopfield神经网络的存贮容量

我们把理论推导与数值模拟相结合，得出了一个较好的误差函数近似解析式。应用该解析式分析了Ｈｏｐｆｉｅｌｄ神经网络的绝对存贮容量，得到了一更严格的结果

Valence-band offsets of strained heterojunction ZnS/ZnSe

采用基于lMTO-ASA的平均结合能计算方法，研究了在znSXSE1-X衬底上沿（001）方向外延生长的应变层异质结znS/znSE的价带带阶值。研究表明，应变的结果使价带带阶随衬底组分（X）的变化呈非线性且单调的关系；与其他理论计算和实验结果比较，本文的计算结果比较理想The valence-band offsets (VBO) of strained heterojunction ZnS/ZnSe as a function of the alloy composition x of ZnS x Se 1- x substrates are studied using the average-bond-energy theory based on LMTO-ASA method.It is shown that the strain leads to the nonlinear and monotonous variation of VBO's with x .The calculation results are more desirable compared with the theoretical and experimental data previously reported.国家和福建省自然科学基

VALENCE BAND ofFSETS of TERNARY ALLOY HETEROJUNCTIONS (AlP) x (Si 2) 1-x /GaP AND (GaP) x (Si 2) 1-x /GaP

采用基于lMTOASA的平均键能计算方法和原子集团展开方法，研究了两组晶格匹配三元合金异质结（AlP）X（SI2）1-X/gAP和（gAP）X（SI2）1-X/gAP的价带带阶ΔEV（X）值。研究表明，两组异质结的ΔEV（X）值随合金组分X的变化都是非线性的，且表现出非单调的关系。The valence band ofFsets Δ E v(x) as a Function of the alloy compositon x of two typical lattice matched ternary alloy heterojunctions (AlP) x (Si 2) 1-x /GaP and (GaP) x (Si 2) 1-x /GaP are studied by using the average bond energy theory in conjunction with the cluster expansion method.It is shown that the variations of Δ E v(x) at (AlP) x (Si 2) 1-x /GaP and (GaP) x (Si 2) 1-x /GaP are nonlinear and non monotonous.The calculated results of Δ E v are in very good agreement with the data previously reported.国家和福建省自然科学基