P－型金刚石半导体制备及其性能研究

利用热丝化学气相沉积法，以硼酸三甲酯为液态掺杂源，用Ｈ＿２携带，制备出高质量的ｐ型金刚石薄膜。经检测，其晶体结构常数与天然金刚石十分接近。对掺杂样品计算表明，硼掺杂浓度是６．５×１０￣（１９）ｃｍ￣（－３）室温下空穴载流子浓度是８×１０￣（１６）ｃｍ￣（－３），电离率为１．２３／１０００。     

Low-temperature processing of shallow junctions using epitaxial and polycrystalline CoSi2

Cobalt disilicide is grown epitaxially on (100) Si from a 15 nm Co/2 nm Ti bilayer by rapid thermal annealing (RTA) at 900°C. Polycrystalline CoSi₂ is grown on (100) Si using a 15 nm Co layer and the same annealing condition. Silicide/p⁺-Si/n-Si diodes are made using the silicide as dopant source:¹¹B⁺ ions are implanted at 3.5–7.5 kV and activated by RTA at 600–900°C. Shallow junctions with total junction depth (silicide plus p⁺ region) measured by high-resolution secondaryion mass spectroscopy of 100 nm are fabricated. Areal leakage current densities of 13 nA/cm² and 2 nA/cm² at a reverse bias of -5V are obtained for the epitaxial silicide and polycrystalline silicide junctions, respectively, after 700°C post-implant annealing.     

凝胶燃烧-等离子法制备磷灰石型氮掺杂硅酸镧

采用凝胶燃烧-等离子氮杂方法制备了磷灰石型硅酸镧(La9.33Si6O26-1.5xNx)固体电解质,并对氮杂样品进行了XRD、FT-IR和Raman表征,测试了样品的热稳定性及电导率。结果表明:La9.33Si6O26-1.5xNx的六边磷灰石型物相结构不变。氮杂导致硅酸镧晶体结构中[SiO4]的环境发生改变,并影响其振动模式。TG-DSC分析表明氮杂硅酸镧的烧结温度应为1 200℃。在微波功率为300W,作用时间为15min条件下制备的氮杂硅酸镧的烧结体的电导率达1.28×10-2 S.cm-1(800℃)。初步分析认为氮杂导致通道氧空位浓度增加、氧离子迁移速率加快、电导率变大,形成空间电导增强效应。     

金属掺杂改性对纳米TiO2光催化作用的影响

利用过渡金属和稀土金属元素氧化物对氧化钛纳米粉末进行掺杂改性,过渡金属元素锡和稀土元素Pr、Tm、Yb氧化物的掺杂改性对氧化钛有明显的光催化改善作用.     

Template-free preparation of non-metal (B,P,S) doped g-C3N4 tubes with enhanced photocatalytic H2O2 generation

Developing environmentally friendly methods to produce hydrogen peroxide (H2O2) has received increas-ing attention.Photocatalysis has been proved to be a sustainable technology for H2O2 production.Herein,the novel non-metal elements (B,P,and S) doped g-C3N4 tubes (B-CNT,P-CNT,and S-CNT) photocata-lysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C3N4 tubes (CNT) materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H2O2 production with the formation rate constants values of 42.31 μM min-1,24.95μM min-1,and 24.22μM min-1,respectively,which is higher than that of bulk CN (16.40 μM min-1).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electron-hole carriers.The results have shown great potential for the practical application of CNT photocatalysts.     

Influence of reaction conditions on the formation of nanotubes/nanoparticles of polyaniline in the presence of 1‐amino‐2‐naphthol‐4‐sulfonic acid and applications as electrostatic charge dissipation material

BACKGROUND: Poly(1‐amino‐2‐naphthol‐4‐sulfonic acid) and its copolymers with aniline are a new class of conducting polymers which can acquire intrinsic protonic doping ability, leading to the formation of highly soluble self‐doped homopolymers and copolymers. Free ? OH and ? NH₂ groups in the polymer chain can combine with other functional groups that could be present in protective paints which can thus be successfully used as antistatic materials. RESULTS: This paper reports the formation of nanotubes of polyaniline on carrying out oxidative polymerization of aniline in the presence of 1‐amino‐2‐naphthol‐4‐sulfonic acid (ANSA) in p‐toluenesulfonic acid (PTSA) as an external dopant. The presence of ? SO₃H groups in the ANSA comonomer allows the copolymer to acquire intrinsic protonic doping ability. The polymerization mechanism was investigated by analysing the ¹H NMR, ¹³C NMR, Fourier transform infrared and X‐ray photoelectron spectra of the copolymers and homopolymers, which revealed the involvement of ? OH/? NH₂ in the reaction mechanism. Scanning and transmission electron microscopy showed how the reaction route and the presence of a dopant can affect the morphology and size of the polymers. Static decay time measurements were also carried out on conducting copolymer films prepared by blending of 1 wt% of copolymers of ANSA and aniline with low‐density polyethylene (LDPE) which showed a static decay time of 0.1 to 0.31 s on dissipating a charge from 5000 to 500 V. CONCLUSION: Copolymers of ANSA with aniline were synthesized in different reaction media, leading to the formation of nanotubes and nanoparticles of copolymer. Blends of 1 wt% of PTSA‐ and self‐doped copolymers of ANSA and aniline with LDPE can be formulated into films with effective antistatic properties. Copyright © 2009 Society of Chemical Industry     

Vibration fracture resistance of 5052H112 aluminum alloy processed by cold rolling and friction stirring

Hot-rolled Al–3Mg alloy processed by various cold-rolled reductions exhibited excellent vibration fracture resistance, however subsequent friction stirring did not endow better vibration fracture resistance than cold-rolled samples in spite of possessing microstructural refinement and homogenization. The D–N curve under a constant initial deflection amplitude (6.5 mm) also showed that the vibration fracture resistance of cold-rolled specimens increased as a result of the slower crack propagation rate. All samples used in this investigation showed a work hardening feature from the initial stage of the D–N curve, and the deflection amplitude tended to increase as the number of vibration cycles increased. During this ascending stage, slip band cracking and strain hardening in the vicinity of the main crack could be recognized. The D–N curve feature of the cold-rolled samples depicted a longer plateau region while the deflection amplitude was at its maximum. It is suggested that the dislocation tangles introduced by cold rolling can strengthen the matrix. As a result, the deflection amplitude drops could be associated with increasing the dislocation tangles due to prior cold rolling while the main crack achieved a critical crack length.     

Carbon doping and etching in GaxIn1−xAsyP1−y on GaAs substrates using CBr4 by metalorganic chemical vapor deposition

Carbon doping and etching by CBr₄ were studied for Ga_xIn_1−xAs_yP_1−y (0≤y≤1) on GaAs grown by metalorganic chemical vapor deposition. It was found that the hole concentration drastically decreases with decreasing y when the flow rate of CBr₄ is constant. When y is under 0.5, the conduction type of GaInAsP changes ton-type. In the region of 0<y<0.6, the surface morphology was degraded and the carrier compensation became higher than could be estimated from the C concentration. This seems to be due to the micro defects because this range of composition is within the unstable region which is theoretically predicted. The etching effect by CBr₄ was observed during the growth. The rate of etching for InAsP component is about three times larger than that for the GaAsP component. The thermodynamic analysis suggests that the etching is due to the increase of the partial pressure of GaBr and InBr.     

衬底掺杂浓度对深亚微米槽栅PMOSFET特性影响

基于流体动力学能量输运模型，利用二维器件仿真软件MEDICI，对衬底掺杂浓度不同的深亚微米槽栅PMOSFET特性进行了研究，并与相应平面器件的特性进行了对比。研究发现，随着衬底掺杂浓度的提高， 与平面器件相同，槽栅器件的阈值电压提高，漏极驱动能力降低，抗热载流子能力急剧退化；但与平面器件相比，槽栅器件的阈值电压受衬底杂质浓度影响较小；漏极驱动能力及抗热载流子性能随衬底杂质浓度提高的退化则较平面器件小得多。