YON界面钝化层改善HfO2/Ge界面特性的研究

本文采用YON界面钝化层来改善HfO₂栅介质Ge metal-oxide-semiconductor（MOS）器件的界面质量和电特性.比较研究了两种不同的YON制备方法：在Ar+N₂氛围中溅射Y₂O₃靶直接淀积获得以及先在Ar+N₂氛围中溅射Y靶淀积YN再于含氧氛围中退火形成YON.实验结果及XPS的分析表明,后者可以利用YN在退火过程中先于Ge表面吸收从界面扩散的O而氧化,从而阻挡了O扩散到达Ge表面,更有效抑制了界面处Ge氧化物的形成,获得了更优良的界面特性和电特性：较小的CET（1.66 nm）,较大的k值（18.8）,较低的界面态密度（7.79×10¹¹ eV^-1cm^-2）和等效氧化物电荷密度（-4.83×10¹² cm^-2）,低的栅极漏电流（3.40×10^-4 A/cm²@V_g=V_fb+1 V）以及好的高场应力可靠性.     

介质前后双重臭氧处理实现锗/氧化铪间界面钝化

The physical and electrical properties of a Ge/GeO₂/HfO₂/Al gate stack are investigated.A thin interfacial GeO₂ layer（ 1 nm） is formed between Ge and HfO₂ by dual ozone treatments,which passivates the Ge/high-k interface.Capacitors on p-type Ge substrates show very promising capacitance-voltage（C-V） characteristics by using in situ pre-gate ozone passivation and ozone ambient annealing after high-k deposition,indicating efficient passivation of the Ge/HfO₂ interface.It is shown that the mid-gap interface state density at the Ge/GeO₂ interface is 6.4×10¹¹ cm^-2·eV^-1.In addition,the gate leakage current density of the Ge/GeO₂/HfO₂/Al gate stack passivated by the dual ozone treatments is reduced by about three orders of magnitude compared to that of a Ge/HfO₂/Al gate stack without interface passivation.     

新型白光LED荧光粉Y2O3:Ti 3+的光谱性能

采用共沉淀法,在不同的烧结气氛下制备了Y₂O₃:Ti ³⁺粉体,测量了它们的激发、发射光谱以及XRD光谱,观测了形貌。在紫外光激发下,微晶Y₂O₃:Ti ³⁺在439nm附近有较强的发射带,而纳米Y₂O₃:Ti ³⁺在400~500nm范围内出现了强的发射带。随纳米粉体的晶粒尺寸减小,它的发光明显增强,覆盖了整个可见光区。结果表明Y₂O₃:Ti ³⁺纳米粉体有望成为新一代白光LED或汞灯的光转换荧光粉。     

近表面加工技术制备的高性能Ge:B 阻挡杂质带探测器

阻挡杂质带（BIB）探测器是当前远红外天文探测领域的主流探测器。通过近表面加工技术成功制备出了高性能的Ge:B BIB探测器,响应波数范围从50 cm^-1到400 cm^-1。在3.5 K温度和30 mV工作电压下,器件在峰值响应84.9 cm^-1处的响应率达到21.46 A·W^-1,探测率达到4.34×10¹⁴cm·Hz^1/2·W^-1。研究了BIB探测器中界面势垒对响应光谱的影响。提出了一种新的激发模式—电极区内的载流子可以通过光激发的方式越过势垒。此外,还发现了一种增强BIB探测器在小波数处相对响应强度的方法。     

Ge基二维三角晶格光子晶体的光子带隙

导出了二维三角晶格光子晶体的填充系数与正多边形散射子外接圆半径的普适关系,并利用平面波展开法计算了Ge基二维三角晶格光子晶体的光子带隙.计算表明:Ge圆柱置于空气背景中时,可产生TM、TE带隙,TM带隙占优势;随着Ge填充系数的增大,光子带隙的宽度先增大后减小,其中心频率由高频向低频移动;TM模第一带隙宽度在半径为0.14a处达峰值.空气圆柱置于Ge背景中时,可产生TM、TE及完全带隙,TE带隙占优势;随着空气填充系数的增大,光子带隙的宽度先增大后减小,其中心频率由低频向高频移动;TE模第一带隙宽度和最大完全带隙宽度分别在半径为0.46a和0.49a处达峰值.     

Influence of growth conditions on the V-defects in InGaN/GaN MQWs

The influence of the growth temperature,TMIn/TEGa andⅤ/Ⅲratio on the V-defects of InGaN/GaN multi-quantum wells（MQWs） has been investigated and discussed.When the TMIn flow increases from 180 to 200 sccm,the density of V-defects increases from 2.72×10¹⁸ to 5.24×10¹⁸ cm^-2,and the V-defect width and depth increase too.The density also increases with the growth temperature.The densities are 2.05×10⁸,2.72×10¹⁸ and 4.23×10⁸ cm^-2,corresponding to a growth temperature of 748,753 and 758℃respectively.When the NH₃ flows are 5000,6600 and 8000 sccm,the densities of the V-defects of these samples are 6.34×10¹⁸,2.72×10¹⁸ and 4.13×10¹⁸ cm^-2,respectively.A properⅤ/Ⅲratio is needed to achieve step flow growth mode.We get the best quality of InGaN/GaN MQWs at a growth temperature of 753℃TMIn flow at 180 sccm,NH₃ flow at 6600 sccm,a flatter surface and less V-defects density.The depths of these V-defects are from 10 to 30 nm,and the widths are from 100 to 200 nm.In order to suppress the influence of V-defects on reverse current and electro-static discharge of LEDs,it is essential to grow thicker p-GaN to fill the V-defects.     

Y3MgAl3SiO12:Dy 3+,Eu 3+荧光粉的能量传递与暖白光实现

采用高温固相法合成了Dy ³⁺、Eu ³⁺共掺杂Y₃MgAl₃SiO₁₂石榴石型荧光粉。采用XRD、荧光光谱仪等仪器对样品的结构以及光谱特性进行表征,探究了Dy ³⁺/Eu ³⁺在Y₃MgAl₃SiO₁₂基质结构中的光谱特征以及离子间的能量传递机制。在367 nm近紫外光激发下,Y₃MgAl₃SiO₁₂:Dy ³⁺,Eu ³⁺的发射光谱包含Dy ³⁺的6F9/2到6H15/2和6H13/2的电子跃迁特征发射(487 nm蓝光和592 nm黄光)和Eu ³⁺的5D0 7F2 and 5D0 7F4特征发射峰(616 nm和710 nm红光)。在400~500 nm范围内Dy ³⁺发射谱与Eu ³⁺激发谱重叠,表明Dy ³⁺与Eu ³⁺之间存在着能量传递,能量传递的机理为电四极-电四极相互作用。该荧光粉通过调整Dy ³⁺和Eu ³⁺的掺杂浓度比封装近紫外LED芯片,可以实现单基质暖白光LED照明。     

基于超宽β-Ga2O3微米带的日盲光电探测器研究

氧化镓的禁带宽度接近5 eV,是一种极具前景的日盲紫外探测半导体材料。基于碳热还原法生长高质量β-Ga₂O₃微米带制备出MSM(Metal-Semiconductor-Metal)结构光电导紫外探测器,研究了不同的结构对光电器件性能的影响。结果表明等间距叉指电极光电探测器相较于两端电阻型光电探测器有更优异的性能。在10 V/254 nm紫外光照下,其响应度、外部量子效率、比探测率和光响应时间等性能提高明显,其中光电流(I_photo)有接近2个数量级的提升,且-2 V附近光暗电流比值增大至2.29×10⁵。随着叉指电极间距从50μm缩减至20μm,器件I_photo变大,其物理机制归因于阳极附近的耗尽层占据电极间微米带的比例增大引发了更高的光生载流子输运效率。     

Sm3+离子激活Y2MgTiO6橙红色荧光粉的制备及发光性质研究

采用溶胶-凝胶法合成了一系列橙红色发光的Y_2-2xMgTiO₆∶2xSm³⁺(YMT∶2xSm³⁺,0≤x≤0.11)荧光粉。通过粉末X射线衍射仪(XRD)、扫描电子显微镜(SEM)、光致发光激发和发射光谱对样品进行了表征分析。结果表明，所制备的YMT∶Sm³⁺样品为纯相，无任何杂质；荧光粉颗粒尺寸为2～3μm,分散性较好且无明显团聚。在407 nm的近紫外光激发下，样品的发射光谱在500～700 nm波长范围内存在三个显著的发射峰，分别是603 nm(⁴G_5/2→⁶H_7/2)和650 nm(⁴G_5/2→⁶H_9/2)处较强的红光，以及566 nm(⁴G_5/2→⁶H_5/2)处较弱的绿光。Sm³⁺离子...     

掺铜氯化镉晶体的电子顺磁共振谱及局域晶格的理论研究

采用晶体场理论和3d⁹电子组态在平面四角晶场中的g因子和超精细结构常数A的三阶微扰计算公式以及CdCl₂: Cu²⁺晶体的局域结构与EPR谱之间的定量关系,合理解释了CdCl₂: Cu²⁺晶体的EPR谱及局域晶体结构,所得EPR参量与实验观测相符合。研究发现芯极化常数κ≈ 0.2827。平面四角键长的变化为 0.013nm. 因此,CdCl₂晶体中掺杂Cu²⁺后,由于静态Jahn-Teller效应引起的晶格驰豫,导致晶格在平面四角内发生了略微伸长的畸变。     

Ag NPs induced near-infrared emission enhancement of Er3+/Tm3+ codoped tellurite glass

Ag nanoparticles(NPs) were introduced into Er³⁺/Tm³⁺ codoped tellurite glasses prepared using melt-quenching and heat-treated techniques. The glass samples were characterized by the differential scanning calorimeter(DSC), X-ray diffraction(XRD), transmission electron microscopy(TEM) and photoluminescence to reveal the Ag NPs induced broadband near-infrared band emission enhancement of Er³⁺/Tm³⁺ ions. The studied glasses possessed good thermal stability with△T larger than 137 ℃. For glass sample heat-treated at 360 ℃ for 6 h, the nucleated Ag NPs in near-spherical shape with an average diameter about 6.5 nm dispersed in the glass matrix. Under the excitation of 808 nm laser diode(LD), the broadband near-infrared fluorescence emission extending from 1 350 nm to 1 620 nm, owing to the combined contributions from the ³H₄→³F₄ transition of Tm³⁺ at 1.47 μm band and the ⁴I_13/2→⁴I_15/2 transition of Er³⁺ at 1.53 μm band, improved significantly with the introduction of Ag NPs, which is mainly attributed to the increased local electric field. The present results indicate that Er³⁺/Tm³⁺/Ag NPs codoped tellurite glass with good thermal stability is a promising glass material for broadband fiber amplifiers of WDM transmission systems.     

纳米粉体Y2O3:Ti 3+ , Eu3+的光谱性能

采用共沉淀法在氮氢气氛中制备出Y₂O ₃:Ti ³⁺, Eu ³⁺纳米粉体,测量了它的XRD、激发与发射光谱,观测了形貌。通过与Y₂O ₃:Ti ³⁺纳米粉体的光谱比较分析,发现Y₂O ₃中的Ti ³⁺至Eu³⁺存在能量传递,以致紫外至蓝光区域的光,均能使Eu³⁺经5D0→7F2等跃迁通道发射出610nm左右的荧光,于是增强了粉体在红橙光区发光的比重,因此可以调节粉体的发光性能。Y₂O ₃:Ti ³⁺纳米粉体的吸收带从紫外延伸到蓝光区,强荧光带覆盖了整个可见光区,这预示它有望成为新一代白光LED或汞灯的光转换荧光粉。     

低温工艺硅量子点多晶硅TFT非易失性存储器

This paper reports on a successful demonstration of poly-Si TFT nonvolatile memory with a much reduced thermal-budget.The TFT uses uniform Si quantum-dots(size ¹0 nm and density ¹0¹¹ cm^-2) as storage media,obtained via LPCVD by flashing SiH₄/H₂ at 580℃for 15 s on a Si₃N₄ surface.The poly-Si grain-enlargement step was shifted after source/drain formation.The NiSi_x-silicided source/drain enables a fast lateral-recrystallization,and thus grain-enlargement can be accomplished by a much reduced thermal-cycle（i.e., 550℃/4 h）.The excellent memory characteristics suggest that the proposed poly-Si TFT Si quantum-dot memory and associated processes are promising for use in wider TFT applications,such as system-on-glass.     

退火温度对蓝宝石衬底上Mg2Si薄膜质量和光学性质的影响

采用磁控溅射法在蓝宝石衬底上制备了结晶良好的Mg₂Si多晶薄膜，研究了退火温度(375～475 ^oC)对薄膜晶体结构、表面形貌、拉曼光谱和光学性质的影响。X射线衍射(XRD)结果表明，当退火温度为400 ^oC时Mg₂Si(220)衍射峰强度最强，样品结晶质量最好，未见明显可观测的MgO相。扫描电镜(SEM)结果表明，所有样品表面均呈现清晰可见的规则六边形，且退火温度对形貌影响较小。拉曼光谱结果显示所有样品均呈现出Mg₂Si薄膜的特征峰(256 cm^-1附近的F_2g振动模)，同时出现345 cm^-1附近的F_1u(LO)声子模，表明生成样品均为结晶良好的Mg₂Si薄膜。对薄膜光学性质的研究结果表明，随着退火温度升高，样品光学带隙先增大后减小。     

氧分压对脉冲激光沉积β-Ga2O3-δ薄膜光学性能的影响

在不同氧分压下,用脉冲激光沉积法在c-蓝宝石衬底上制备了高质量β-Ga₂O_3?δ薄膜。通过X-射线衍射、远红外反射光谱、X-射线光电子能谱和紫外-可见-近红外透射光谱系统地研究了β-Ga₂O_3?δ薄膜的晶格结构、化学计量比和光学性质。X-射线衍射分析表明,所有沉积的薄膜以(-201)晶向方向生长。透射光谱显示薄膜在255 nm以上的紫外-可见-近红外波段具有80%以上的高透明度,同时在255 nm附近有一个陡峭的吸收边。此外,利用Tauc-Lorentz(TL)色散函数模型和Tauc公式,我们提取了β-Ga₂O_3?δ薄膜的光学常数和光学直接带隙。更进一步,我们通过理论计算解释了氧气分压对β-Ga₂O_3?δ薄膜光学性质的影响。     

用于受控热核聚变的光致离解激光器

1961年 C. Γ. Pаутиан等提出了光致离解激光器的特性是吸收泵浦辐射带足够宽（~10³厘米^-1)，这接近于固体激光的吸收带，同时包。含有较窄的荧光光谱线10^—2~10^-1厘米^-1,这就有可能获得较髙的增益系数和较低的振荡阈值。     

Physical properties of sprayed antimony doped tin oxide thin films:The role of thickness

Transparent conducting antimony doped tin oxide（Sb:SnO₂） thin films have been deposited onto preheated glass substrates using a spray pyrolysis technique by varying the quantity of spraying solution.The structural, morphological,X-ray photoelectron spectroscopy,optical,photoluminescence and electrical properties of these films have been studied.It is found that the films are polycrystalline in nature with a tetragonal crystal structure having orientation along the（211） and（112） planes.Polyhedrons like grains appear in the FE-SEM images. The average grain size increases with increasing spraying quantity.The compositional analysis and electronic behaviour of Sb:SnO₂ thin films were studied using X-ray photoelectron spectroscopy.The binding energy of Sn3d_5/2 for all samples shows the Sn⁴⁺ bonding state from SnO₂.An intensive violet luminescence peak near 395 nm is observed at room temperature due to oxygen vacancies or donor levels formed by Sb⁵⁺ ions.The film deposited with 20 cc solution shows 70%transmittance at 550 nm leading to the highest figure of merit(2.11×10^-3Ω^-1). The resistivity and carrier concentration vary over 1.22×10^-3 to 0.89×10^-3Ω·cm and 5.19×10²⁰ to 8.52×10²⁰ cm^-3,respectively.     

Bi3+, Eu 3+, Tb3+ 掺杂Lu3TaO7的发光性能研究

采用固相反应法制备了Bi ³⁺ 、Eu³⁺ 、Tb³⁺ 掺杂的Lu₃TaO₇。测量了样品的X射线衍射谱、激发和发射光谱及荧光衰减曲线。三种离子掺杂的Lu₃TaO₇均呈现出强的荧光发射,其中Bi³⁺具有峰位在431 nm处的一强发射宽带,衰减寿命为16.8 μs,Eu ³⁺ 、Tb ³⁺ 则表现出稀土离子的特征锐发射峰,衰减寿命分别为1.26 ms和1.20 ms。因此,它们均是具有潜在应用前景的重闪烁体材料。     

GSA和ESA双波长泵浦2.3 μm波段Tm:YAP激光器

Tm³⁺离子³F₄能级的粒子数捕获效应是影响2.3μm掺铥激光器高效运转的重要因素。报道了基态吸收（GSA,³H₆→³H₄）和激发态吸收（ESA,³F₄→³H₄）双波长泵浦2.3μm波段Tm∶YAP激光器。使用785 nm（GSA）和1470 nm（ESA）双波长泵浦方案能够精准减少³F₄能级的粒子数,有效增加³H₄能级粒子数布居。在双波长泵浦沿a轴切割的Tm∶YAP晶体中,使用透过率T=1.5%的输出镜,2274 nm和2383 nm双波长激光最大输出功率为2.28 W,相比于单波长泵浦方案提高了65.2%。使用T=2.8%输出镜,2383 nm激光的最大输出功率为942 mW,较单波长泵浦方案提高了84.3%。通过采用特殊镀膜的输出镜,进一步实现了2446 ...     

用光谱法研究光敏剂血卟啉单甲醚对肿瘤细胞光动力作用的分子机制

测定了光敏剂血卟啉单甲醚对人宫颈癌细胞HeLa光敏作用后的傅里叶红外光谱。结果显示:光敏作用后,HeLa细胞磷酸二酯基团的对称伸缩振动峰1085cm^-1和不对称伸缩振动峰1246cm^-1蓝移,强度下降:蛋白质酰胺Ⅰ带1656cm^-1发生蓝移,酰胺Ⅱ带1546cm^-1出现红移;CH₂对称伸缩振动峰2858cm^-1,峰位蓝移2cm^-1,峰值明显减弱:细胞的蛋白质和核酸谱峰面积比值D1085/D1546降低。提示细胞中的DNA、蛋白质和磷脂结构受到损伤。结果表明:DNA、蛋白质和磷脂是血卟啉单甲醚光敏作用的主要靶分子。