铜过量对CuxAlO2(1≤x≤1.06)电学性能的影响

采用溶胶.凝胶法制备了铜铁矿结构CuxAlO2陶瓷体材.当1≤x＜1.04时,样品为纯铜铁矿相,当x≥1.04时,样品中出现了微弱的CuO相.样品Cu1.04AlO2的室温电导率比名义组分CuAlO2大了近一个数量级.研究表明,替位式缺陷CuAl(Cu2+离子取代Al3+离子)是导致电导增加的主要受主缺陷机制,Cu过量CuxAlO2的分子式可更准确地表示为Cu(Al1-yCuy)O2.     

21≤Z≤26类氟离子精细结构能级和跃迁波长的MCDF计算

本文用相对论多组态Dirac-Fock广义平均能级模型(MCDF-EAL)计算了可能成为激光工作物质的类氟ScXIII、TiXVI、VXV、CrXVI、MnXVII和FeXVIII的2s~2p~5、2s2p~6、2s~22p~43s、2s~22p~43p组态的精细结构能级和若干3s-3p跃迁波长值。预言了一些离子的3p组态能级和3s-3p跃迁波长值。     

铜过量对CuxAlO2(1≤x≤1.06)电学性能的影响

采用溶胶.凝胶法制备了铜铁矿结构CuxAlO2陶瓷体材.当1≤x＜1.04时,样品为纯铜铁矿相,当x≥1.04时,样品中出现了微弱的CuO相.样品Cu1.04AlO2的室温电导率比名义组分CuAlO2大了近一个数量级.研究表明,替位式缺陷CuAl(Cu2 离子取代Al3 离子)是导致电导增加的主要受主缺陷机制,Cu过量CuxAlO2的分子式可更准确地表示为Cu(Al1-yCuy)O2.     

研发≤65nm工艺的最新进展

本文介绍了当前世界顶级半导体公司、材料公司、设备公司和微电子科研中心研发65nm、45nm、32nm和5nm工艺的最新进展和成果。     

Pb_(1-X)Ge_XTe(0.05≤X≤0.11)扩散结光伏红外探测器

用P型Pb_(1-x)Ge_xTe(0.05≤x≤0.11)通过锑杂质扩散形成n-p结已制成光伏红外探测器。在77和195K之间的温度下进行了测量,其长波响应截止是3.5～4.5微米。禁带宽度温度系数在低于铁电居里温度时为正而在高于该温度时即转变为负。     

NaxCoO2（0．75≤x≤1．0）中超结构的透射电镜研究

近期 ,日本科学家Takada等发现了新型层状水合物超导体Na0 3 CoO2 ·1 3H2 O[1] 。该超导体具有层状结构 ,属于强关联体系 ,由于它在导电性和晶体结构上均类似于高温超导体 ,所以引起了科学界的广泛关注。我们用传统的固态反应法得到其母体NaxCoO2[2 ] ,并对其进行了透射电子显微镜研究。图a和b是Na0 75CoO2 的分别沿 [0 10 ]和 [0 0 1]带轴的电子衍射图 ,所有衍射斑点都能准确地指标化 ,分析表明该化合物为六方晶系 ,其空间群为P6 3 mmc ,晶胞参数为a =0 2 8nm ,c =1 0 92nm。图c和d是温度为 10 0K时所拍摄的电子衍射花样 ,显示…     

MBE生长InGaAs／n0.32≤x≤0.52Al1—xAs MM—HEMT材料

在GaAs衬底上利用分子来外延技术生长了不同In组分的Metamorphic HEMT(简称MM—HEMT)。通过对MM—HEMT材料中台阶式缓冲层材料种类、台阶宽度、初始组分以及生长温度等生长参数、生长条件和结构参数进行优化，得到了具有良好电学性能的MM—HEMT材料，其二维电子气迁移率和浓度指标与国外同期水平相当。     

等离子体化学气相沉积非晶SiOx∶H（0≤x≤2.0）薄膜的红外光谱

以等离子体化学气相沉积法（PECVD）在300℃下用SiH4和O2混合气体制备了非晶SiOx∶H (a-SiOx∶H,0≤x≤2.0) 薄膜,并用傅里叶红外光谱（FT-IR）测试分析了薄膜中的Si—O—Si键红外吸收特性.Si—O—Si伸缩振动模在1050cm-1和1150cm-1附近有两个吸收峰,而弯曲振动模在800cm-1附近有一个吸收峰.1050cm-1和1150cm-1吸收带的吸收强度之和Isum与薄膜中的Si原子密度NSi之比Isum/NSi在氧含量x=0—2.0的范围内和x成正比.求得氧含量比例系数ASiO（Si—O谐振子强度的倒数）为1.48×1019cm-1.另外,a-SiO2薄膜的800cm-1和1050cm-1吸收峰的表观吸收系数αapp和膜厚d成正比:αapp=kd,求得吸收比例系数k分别为3.2×103和2.9×104cm-1.比较发现k值的大小和a-SiO2薄膜的致密性密切相关.利用上述ASiO和k比例系数,可快速简便地用非破坏性的FT-IR测定PECVD a-SiOx∶H的氧含量x以及a-SiO2的膜厚d.     

等离子体化学气相沉积非晶SiO_x∶H(0≤x≤2.0)薄膜的红外光谱

以等离子体化学气相沉积法 (PECVD)在 30 0℃下用 Si H4和 O2 混合气体制备了非晶 Si Ox∶ H(a- Si Ox∶ H,0≤ x≤ 2 .0 )薄膜 ,并用傅里叶红外光谱 (FT- IR)测试分析了薄膜中的 Si— O— Si键红外吸收特性 .Si— O— Si伸缩振动模在 10 5 0 cm- 1和 115 0 cm- 1附近有两个吸收峰 ,而弯曲振动模在 80 0 cm- 1附近有一个吸收峰 . 10 5 0 cm- 1和115 0 cm- 1 吸收带的吸收强度之和 Isum与薄膜中的 Si原子密度 NSi之比 Isum/ NSi在氧含量 x =0— 2 .0的范围内和 x成正比 .求得氧含量比例系数 ASi O (Si— O谐振子强度的倒数 )为 1.48× 10 1 9cm- 1 .     

33≤Z≤40类氟离子精细结构能级和跃迁波长的相对论多组态Dirac-Fock计算

本文用相对论多组态Dirac-Fock广义平均能级模型计算了可能成为激光工作物质的类氟AsXXV、SeXXVI、BrXXVII、KrXXVIII、RbXXIX、SrXXX、YXXXI和ZrXXXII的2s~2p~5、2e2p~6、2s~22p~43s、2s~2p~43p组态的各30个精细结构能级和54个3s-3p跃迁波长,大部分计算值都是本文首次预言的。     

MBE生长InGaAs/In_(0.32≤x≤0.52)Al_(1-x)As MM-HEMT材料

在GaAs衬底上利用分子束外延技术生长了不同In组分的MetamorphicHEMT(简称MM-HEMT)。通过对MM-HEMT材料中台阶式缓冲层材料种类、台阶宽度、初始组分以及生长温度等生长参数、生长条件和结构参数进行优化,得到了具有良好电学性能的MM-HEMT材料,其二维电子气迁移率和浓度指标与国外同期水平相当。     

58≤Z≤71类氖离子2p~53l能级的相对论多组态Dirac-Fock计算

本文用相对论多组态Dirao-Fook广义平均模型(MCDF-EAL)计算了58≤Z≤71的2P~53s、2P~53p和2P~53d组态的各27条精细结构能级,以及其作为等离子体激光工作物质所可能发射出的激光波长值。     

Thermal stability of lead-free CH3NH3SnxI3 systems (0.9 ≤ x ≤ 1.1) for photovoltaics

Methylammonium-tin-iodide (MASn_xI₃, 0.9 ≤ x ≤ 1.1) systems were prepared by precipitation process in aqueous solutions. The “as prepared” MASn_xI₃ systems exhibited a tetragonal crystalline phase (space group I4cm) with polyhedral crystallites (length 50–400 µm). The as prepared samples were annealed at T = 150 °C for t = 8 h under nitrogen and synthetic air. Under nitrogen, the CH₃NH₃Sn_xI₃ systems adopt nearly-cubic tetragonal structure (space group P4mm) with crystallites of 2–4 µm length whereas a degradation process with formation of non-crystalline phases occurred in air. The differential thermal analysis (DTA) profile in nitrogen revealed events at T = 247 °C, T = 297 °C (decomposition of CH₃NH₃Sn_xI₃ systems into methylamine (CH₃NH₂), hydroiodic acid (HI) and SnI₂), and in the range T = 342–373 °C (melting of SnI₂) respectively. The thermal profile in air showed endothermic events at T = 139 °C and T = 259 °C with additional events at onset temperatures of T = 337 °C and T = 423 °C respectively which correspond to the formation of Sn(IV)-O binds and to the decomposition of methylamine. Static thermogravimetry analysis (TG), performed at T = 85 °C and T = 150 °C for t = 2 h, revealed a linear weight loss as a function of the time. The optical absorption spectra displayed absorbance edges in near infrared range, at 1107.0 nm (x = 0.9), 1098.6 nm (x = 1.0) and 1073.2 nm (x = 1.1) respectively.     

Q≤＞0.707对频率响应影响的证明

介绍了在电路理论教学中 Q≤ >0 .70 7对频率响应影响的证明方法 ,若在教学中补充该内容 ,则能加深学生对该课程相关内容的理解。     

The Band-Structure Parameters of Bi1 –xSbx (0 ≤ x ≤ 0.15) Thin Films on Substrates with Different Thermal-Expansion Coefficients

Semiconductors - The results of calculation of the charge-carrier concentration in bismuth–antimony films on substrates with different coefficients of thermal expansion are reported. The...     

Synthesis and Microwave Dielectric Properties of SrLa4−x Pr x Ti5O17 (0 ≤ x ≤ 4) Ceramics

Single-phase ceramics in the SrLa_4?x Pr _x La₄Ti₅O₁₇ (0 ≤ x ≤ 4) series were processed via a solid-state sintering route. X-ray diffraction analysis revealed single-phase ceramics for all the compositions. The molar volume (V _m) decreased while the theoretical density (ρ _th) increased with increase in the Pr content. Substitution of Pr³⁺ decreased the relative permittivity (ε _r) and temperature coefficient of resonant frequency (τ _f) due to its smaller ionic polarizability (α _d) and ionic radius than La³⁺. In the present study, ε _r ≈ 54.2, Q _u f ₀  ≈ 7935 GHz, and τ _f  ≈ ?20.3 ppm/°C were achieved for the composition with x = 2 (i.e., SrLa₂Pr₂Ti₅O₁₇).     

Role of intervalley scattering in the radiative recombination in Pb1 − x Eu x Te alloys (0 ≤ x ≤ 1)

Measurements of the photoluminescence from epitaxial layers of Pb_{1 ? x} Eu _x Te alloys with 0 ≤ x ≤ 0.32 are carried out. It is found that the luminescence intensity decreases with increasing Eu content and, already for x as low as about 0.1, drops by more than one order of magnitude. No luminescence is observed for 0.2 < x ≤ 0.32. This behavior is explained by the fact that, for x ≈ 0.1, the absolute minimum in the conduction band changes from the L to X point, which results in the scattering of nonequilibrium electrons to the X valley and, thus, causes a decrease in the quantum efficiency of the emission. According to published data, for x > 0.85, optical transitions also take place with the participation of the X valley; in this case, the emission is governed by the formation of magnetic polarons. The temperature dependences of the band gap are determined for 0 ≤ x ≤ 0.11. These dependences have a wide linear region characterized by a positive dE _g /dT coefficient, which decreases with the Eu content to become negative in pure EuTe.     

采用移相掩模技术实现≤0.2μmi线光刻

本文提出了一种适于制作孤立图形的新的移相掩模方法,这种新的移相掩模仅由移相器图形组成。移相器的边缘线(PEL)起遮光掩蔽作用。光强计算表明:在相同的照明条件下,由移相器边缘线得到暗场,其光强分布比铬掩模的更为陡峭。采用移相器边缘线掩模及i线步进光刻机(镜头数值孔径NA=0.42,光相干因子σ=0.5),就可制作出线条(正性抗蚀剂)和间隔(负性抗蚀剂)尺寸≤0.2μm的抗蚀剂图形,图形线宽可通过曝光量进行控制。用LMR-UV负性抗蚀剂,在1.5μm宽的聚焦范围内,可制作出0.15μm宽的窗口图形。对特征尺寸很少的方孔图形,可采用一对移相器边缘线掩模和负性抗蚀剂,通过两次重叠曝光法来制作。使第二个曝光掩模上的移相器边缘线与第一个曝光掩模上的移相器边缘线构成直角正交,于是,在大于1.5μm的聚焦范围内,在两边缘线的交叉处,即可成功地形成0.2μm的方孔图形。用同样的方法及正性抗蚀剂(PFR-TT15),如果留膜厚度没有损耗,0.2μm尺寸的柱图形也可制作出来。