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

Valence Subband Structure and Optical Gain of InGaAs/InP Quantum Wire

采用有效质量理论 6带模型 ,计算了 In0 .53Ga0 .4 7As/ In P量子线的光学性质 ,具体计算了In0 .53Ga0 .4 7As/ In P量子线的能带结构、态密度、载流子浓度、光学跃迁矩阵元和光学增益谱 ,并把量子线的光学增益谱和量子阱的光学增益谱作了比较。福建省自然科学基金资助课题 (No.E9910 0 0 5

Growth of High-reflectivity AlN/GaN Distributed Bragg Reflectors in Blue Region

采用金属有机物化学气相沉积方法制备了蓝光波段高反射率Aln/gAn分布布拉格(dbr)反射镜。利用金相显微镜、扫描电子显微镜、原子力显微镜以及分光光度计等测量手段对样品的物理特性进行了分析表征。结果显示样品的表面有少量圆形台面结构和裂纹出现,但在其他区域,样品具有较为平整的表面。该样品在462.5 nM附近获得最大反射率99.4%,表面均方根粗糙度小至2.5 nM。分析表明,所得dbr达到了制备gAn基垂直腔面发射激光器的要求。One high-reflectivity AlN/GaN distributed Bragg reflector(DBR) in blue region was grown with the method of metalorganic chemical vapor deposition(MOCVD).perties of the sample were analyzed by using,scanning electron microscope(SEM),atomic force microscopy(AFM) and spectrophotometer.Except for the circular mesa structure and a few cracks observed on the surface,the sample showed a rather smooth surface.A peak reflectivity of 99.4% was observed around 462.5 nm and the surface roughness was as small as 2.5nm.The properties of the DBR meet the requirements of GaN-based vertical cavity surface emitting lasers(VCSEL).国家“863”计划资助项目(2006AA03Z409

Average-bond-energy and Fermi Level on Free Electronic Band

【中文摘要】 根据半导体自由电子能带模型 ,文中在面心立方 (fcc)晶体、体心立方 (bcc)晶体和 6角密堆积 (hcp)晶体中研究自由电子能带的平均键能 Em 和费米能级 EF 的关系 ,并得出自由电子能带的平均键能 Em 相当于费米能级 EF 的研究结果。其结果有助于了解平均键能 Em 的物理实质 ,同时也为自由电子系统提供一种通过自由电子能带计算费米能级 EF(或费米半径 k F)的方法 【英文摘要】 Based on the free electronic band model, we study the relationship between average bond energy E m and Fermi level E F in face centered cubic (fcc) crystal, body centered cubic (bcc) crystal and hexagonal closed packed structure (hcp) crystal. It is concluded that the average bond energy E m is equivalent to the Fermi level E F on free electronic band. The results may help to understand the physical conception of average bond energy E m and also supply a method to calcu...高校博士点基金 (9538409); 福建省自然科学基金 (E990005)资助项

The Diagnosis of the Ancient Trees of Ficus microcarpa

通过对鼓浪屿古榕树的普查,选择其健康诊断的生长指标和生理指标,包括当年生枝叶、果实生长状况、叶绿素荧光等,对不同生长势的古榕树进行分析,旨在探讨基于生长指标与生理指标相结合的古榕树的健康诊断方法,为古榕树的养护与复壮提供依据。结果表明,生长指标与生理指标能较一致地指示古榕树的健康状况。因此,可通过生长指标与生理指标相结合的方法诊断古榕树的健康状况。Based on the general investigation and analysis of the ancient trees of Ficus microcarpa at Gulangyu by use of the growth indices and the physiological indices,such as the growth status of annual branches,leaves and fruits and the chlorophyll fluorescence,the diagnosis of the ancient trees of Ficus microcarpa with different growth vigor was discussed to provide evidence for their maintenance and rejuvenation.The results indicated that the growth indices and the physiological indices could consistently instruct the health status of the ancient trees of Ficus microcarpa.Thus the diagnosis by the combination of the growth indices and the physiological indices could be applied to the ancient trees of Ficus microcarpa.鼓浪屿万石山国家级风景名胜区科技项目资助(GW2008

MOCVD growth of high-reflectivity AlN/GaN distributed Bragg reflectors

利用金属有机物化学气相沉积(MOCVD)方法在蓝宝石c面衬底上制备出高反射率AlN/GaN分布布拉格反射镜(DBR)。利用分光光度计测量,在418 nm附近最大反射率达到99%。样品表面显微照片显示,有圆弧形缺陷和少量裂纹出现;在缺陷和裂纹以外的区域,DBR具有较为平坦的表面,其粗糙度在10μm×10μm面积上为3.3 nm左右。样品的截面扫描电镜(SEM)照片显示,DBR具有良好的周期性。对反射率和表面分析的结果表明,该样品达到了制备GaN基垂直腔面发射激光器(VCSEL)的要求。A high reflectivity AlN/GaN distributed Bragg reflector(DBR) is grown on c-plane sapphire substrate by metalorganic chemical vapor deposition(MOCVD).A peak reflectivity of 99% is observed around 418 nm by spectrophotometer.Compass-shape defects and a few cracks are observed on the surface.The surface root mean square(RMS) of roughness in the flat area is around 3.3 nm over a 10 μm×10 μm area.The cross-sectional scanning electron microscope(SEM) image reveals the good periodicity of DBR.Considering the peak reflectivity and surface morphology,the DBR can be used to fabricate GaN-based vertical cavity surface emitting laser(VCSEL).国家高技术研究“863”计划资助项目(2006AA03Z409