Fine Structures of Energy Levels of DX Centers in

杂质和缺陷一直是半导体材料的重要研究课题。n型混晶材料的DX中心由于其特异的性质如持久光电导(PPC)效应等，更引起了人们的兴趣。至目前为止，虽然对DX中心的物理起源、精细结构等进行了许多讨论，但有许多问题仍有待解决。因此，随着AlxGa1-xAs，GaAs1-xPx等III-V族混晶材料在各种新兴光电器件中越来越广泛的应用，对III-V族混晶中DX中心的深入研究具有更重要的应用价值和学术意义。 本文将报告采用定电容电压瞬态法，测量了不同温度下n型AlxGa1-xAs:Sn（x=0.26）中DX中心电子热俘获过程和不同俘获时间后电子热发射过程的定电容电压瞬态，得到俘获瞬态谱随着温度的升高...Impurities and defects is an important subject in the semiconductor research work. DX centers, one of deep centers related to donors, have been found to be the universal deep states in most of III-V alloy semiconductors. They are characterized by several unusual properties, such as a large difference between thermal and optical ionization energies and extremely small electron capture cross section...学位：理学硕士院系专业：物理与机电工程学院物理学系_凝聚态物理学号：19982400

AlGaAs∶Sn中DX中心电子俘获势垒的精细结构

Voltage transients due to the thermal electron capture and emission of DX centers in n-type Sn-doped Al0.26Ga0.74As were measured by the constant capacitance technique and transformed by Laplace defect spectroscopy (LDS). By analyzing the variations of discrete emission rates with different capture periods, corresponding relations between discrete capture and emission rates and capture coefficients were determined. The fine structures of electron capture barriers of the Sn-related DX centers were obtained by linear fitting the data of temperature-dependences of the capture coefficients. The results calcuated by using the first principle pseudopotential method show that the fine structures of the capture barriers mainly contribute to Al/Ga at different local configurations near Sri atoms due to the alloy random effect

Defects in ⅢNitrides Epilayers

【中文摘要】 采用光荧光和阴极荧光方法 ,对 Ga N外延层中的黄色和蓝色发光进行测量分析 ;同时 ,采用原子力显微镜、扫描电镜及其能谱测量外延层中的缺陷。结果表明 ,黄色和蓝色发光与残留杂质有关。采用第一原理计算结果显示 ,残留 C、O杂质、本征缺陷等是黄色和蓝色的可能物理起源。采用原子力显微镜、扫描电镜、透射电镜及其能谱对 Ga N/Al Ga N异质结中的纳米管进行观测 ,了解了纳米管的形貌。结果表明 ,构成纳米管的小面可能是外延过程中表面吸附引起的 ;计算结果显示 ,纳米管形貌变化与 Ga N/Al Ga N界面处晶格失配应力有关。采用透射电镜观察外延层中沉积物及其周围位错的结构表明 ,沉积物附近应力的存在是位错产生的主要原因 【英文摘要】 Blue and yellow luminescence bands in undoped GaN epilayers were investigated and related to main residual C and O impurities by photoluminescence, which are suggested to be attributable to the electron transitions from O N states to V Ga states and between the inner levels of the C N O N complex, respectively, according to ab initio local density functional calculations. Larger nanopipes in undoped GaN/AlGaN hetero epilayers were imaged as dodecagonal pyramidal indentations, using atomic fo...国家重点基础研究发展规划项目 (批准号 :001CB610505 );国家自然科学基金 (批准号 :69976023、90206030、10134030 );福建省自然 科学基金 (批准号 :A0020001);教育部部分资助项

Microstructural Dissection of Zinc Sulfide Thin Films

用X射线衍射和X射线光电子能谱技术，对分舟热蒸发法研制的掺铒（Er）硫化锌直流电致发光薄膜及硫化锌粉料进行剖析，获得薄膜表面及粉料的构态信息，讨论了影响微晶薄膜质量的主要因素。The zinc sulfide DCEL thin films doped with erbium, prepared by thermal evaporation with two boats, are analysed with XRD and XPS technologies. The structure state information of ZnS powder and thin film surface is obtained. The factors influencing on the quality of microcrystalline thin films are discussed as well.福建省自然科学基

Fine structures of electron capture barriers of the DX centers in Sn-doped AlGaAs

采用定电容电压法 ,测量了n型Al0 2 6 Ga0 74 As∶Sn中DX中心电子热俘获瞬态 ,以及不同俘获时间后的电子热发射瞬态 ;并对瞬态数据进行数值Laplace变换 ,得到其Laplace缺陷谱 (LDS) .通过分析LDS谱 ,确定了电子热俘获和热发射LDS谱之间的对应关系 ,从而得到热俘获系数对温度依赖关系 ,以及与Sn相关的DX中心部分电子热俘获势垒的精细结构 ;通过第一原理赝势法计算表明 ,Sn附近的Al Ga原子的不同配置是电子热俘获势垒精细结构产生的主要原因Voltage transients due to the thermal electron capture and emission of DX centers in n type Sn doped Al 0.26 Ga 0.74 As were measured by the constant capacitance technique and transformed by Laplace defect spectroscopy (LDS). By analyzing the variations of discrete emission rates with different capture periods, corresponding relations between discrete capture and emission rates and capture coefficients were determined. The fine structures of electron capture barriers of the Sn related DX centers were obtained by linear fitting the data of temperature dependences of the capture coefficients. The results calcuated by using the first principle pseudopotential method show that the fine structures of the capture barriers mainly contribute to Al/Ga at different local configurations near Sn atoms due to the alloy random effect.国家“8 63”计划 (批准号 :715 0 10 0 0 2 2 );; 国家自然科学基金 (批准号 :699760 2 3);; 福建省自然科学基金 (批准号 :A0 0 2 0 0 0 1)资助的课题~

TWO DX-LIKE CENTERS IN Sn-DOPED AlGaAs ALLOY SEMICONDUCTORS

【中文摘要】 在测得Ａｌ０．２６Ｇａ０．７４Ａｓ:Ｓｎ混晶中两类类ＤＸ中心的电子热俘获势垒精细结构后,研究和确定了其相关的束缚能、晶格驰豫能和光离化能．采用第一原理赝势法的计算和分析结果表明,Ｓｎ施主杂质次近邻Ａｌ/Ｇａ原子的不同局域组分所引起的Ｓｎ杂质及其最近邻Ａｓ原子的不同晶格驰豫,是产生两类类ＤＸ中心能级精细结构的主要原因． 【英文摘要】 The corraspondent values of binding energy, lattices relaxation energy and optical ionization energy of two DX - like centers in Al0.26Ga0.74 As: Sn alloy semiconductors were deduced after their fine structures of capture barrier were obtained. The ab initio calculations show that fine structures of the two DX-like centers are mainly contributed to different local configurations of the second nearest Al/Ga atoms of Sn donor impurities caused by the alloy random effect.国家“863”计划(批准号715－010－0022);国家自然科学基金(批准号69976023);福建省自科学基金(批准号A0020001)以及教育部基金部分资助课

TWO DX-LIKE CENTERS IN Sn-DOPED AlGaAs ALLOY SEMICONDUCTORS

在测得Ａｌ０．２６Ｇａ０．７４Ａｓ:Ｓｎ混晶中两类类ＤＸ中心的电子热俘获势垒精细结构后,研究和确定了其相关的束缚能、晶格驰豫能和光离化能．采用第一原理赝势法的计算和分析结果表明,Ｓｎ施主杂质次近邻Ａｌ/Ｇａ原子的不同局域组分所引起的Ｓｎ杂质及其最近邻Ａｓ原子的不同晶格驰豫,是产生两类类ＤＸ中心能级精细结构的主要原因．The corraspondent values of binding energy, lattices relaxation energy and optical ionization energy of two DX - like centers in Al0.26Ga0.74 As: Sn alloy semiconductors were deduced after their fine structures of capture barrier were obtained. The ab initio calculations show that fine structures of the two DX-like centers are mainly contributed to different local configurations of the second nearest Al/Ga atoms of Sn donor impurities caused by the alloy random effect.国家“863”计划(批准号715－010－0022);;国家自然科学基金(批准号69976023);;福建省自科学基金(批准号A0020001)以及教育部基金部分资助课

Fine structures of electron capture barriers of the DX centers in Sn-doped AlGaAs

【中文摘要】 采用定电容电压法 ,测量了n型Al0 2 6 Ga0 74 As∶Sn中DX中心电子热俘获瞬态 ,以及不同俘获时间后的电子热发射瞬态 ;并对瞬态数据进行数值Laplace变换 ,得到其Laplace缺陷谱 (LDS) .通过分析LDS谱 ,确定了电子热俘获和热发射LDS谱之间的对应关系 ,从而得到热俘获系数对温度依赖关系 ,以及与Sn相关的DX中心部分电子热俘获势垒的精细结构 ;通过第一原理赝势法计算表明 ,Sn附近的Al Ga原子的不同配置是电子热俘获势垒精细结构产生的主要原因 【英文摘要】 Voltage transients due to the thermal electron capture and emission of DX centers in n type Sn doped Al 0.26 Ga 0.74 As were measured by the constant capacitance technique and transformed by Laplace defect spectroscopy (LDS). By analyzing the variations of discrete emission rates with different capture periods, corresponding relations between discrete capture and emission rates and capture coefficients were determined. The fine structures of electron capture barriers of the Sn related DX centers...国家“863”计划 (批准号 :7150100022 ); 国家自然科学基金 (批准号 :69976023);福建省自然科学基金 (批准号 :A0020001)资助的课