纳米SiC蓝光发射的研究

在４．６８ｅＶ的激光激发下，室温ＣＶＤ合成的纳米ＳｉＣ粉体，可发射４７５ｎｍ的蓝光，经６００～１１００℃在Ｎ２气氛下进行快速退火（ＲＴＡ）处理，其荧光强度随退火温度升高而增强，当Ｔ≥９００℃时，荧光强度下降，但发光峰位与退火温度无关．通过ＸＲＤ、ＩＲ、ＴＥＭ、ＸＰＳ等研究，认为纳米ＳｉＣ中与氧有关的缺陷可能是引起４７５ｎｍ蓝光发射的主要原因     

Ge：SiO2的光敏缺陷的研究

研究了Ｇｅ；ＳｉＯ２光敏缺陷的特性，分别在４８８ｎｍＡｒ离子激光与１９３ｎｍＡｒ准分子激光作用下，由紫外吸收带，激光荧光的测量实验及电子自旋共振实验，发现光纤中５．１ｅＶ锗缺陷吸收带实验上是由５．０６ｅＶ可光致漂白带与５．１７ｅＶ不可漂白带组成；２９５ｎｍ的激发荧光与５．０６ｅＶ的缺氧锗缺陷对应，随５．０６ｅＶ缺陷吸收带的漂白而衰减；     

电子关联对C60激子极化子的影响

本文采用扩展的Ｈｕｂｂａｒｄ模型，在电子－晶格耦合的紧束缚近似下，研究了光激发下的Ｃ₆₀，分子的激子态和极化子态。我们发现，电子关联效应相当敏感地影响到单态和三态激子的束缚能。同时，Ｃ₆₀分子动力学晶格弛豫使激子极化子得以形成。光激发下的Ｃ₆₀分子，在电子相互作用Ｕ～５．０ｅＶ，Ｖ～２．０ｅＶ时，能够定性地解释荧光发射谱。 关键词：     

态布居测热核的核温度及其与碰撞参数的关系

测量了２５ＭｅＶ／ｕ^４０Ａｒ＋¹⁹⁷Ａｕ反应中两裂片符合下的小角α-α关联．由α-α关联函数提取了⁸Ｂｅ核的相对态布居和热核的核温度．实验测得发射温度随碰撞参数而稍有变化，从中心碰撞的４ＭｅＶ变化至周边碰撞的３.８ＭｅＶ．在周边碰撞中，观察到发射温度随着粒子能量的增加而升高     

In0.49Ga0.51P中缺陷的俘获行为

利用深能级瞬态谱（ＤＬＴＳ）和瞬态光电阻率谱（ＴＰＲＳ）研究了利用金属有机物化学汽相沉淀（ＭＯＣＶＤ）生长的未有意掺杂的Ｉｎ０．４９Ｇａ０．５１Ｐ中缺陷对载流子的俘获过程和发射过程．利用ＤＬＴＳ测量观测到了一个激活能为０．３７ｅＶ的缺陷,该缺陷的俘获势垒值介于１８０ｍｅＶ到２４０ｍｅＶ之间．该缺陷的俘获势垒值的大的分布被解释为缺陷周围原子重组的微观波动．在研究中发现研究这些缺陷的俘获过程比发射过程更有效,俘获势垒为０．０６ｅＶ和０．４０ｅＶ的两个缺陷在俘获过程中被观测到,而在发射过程中并没有观测到     

用于等离子体电位测量的电容探针和发射探针

本文给出了发射探针和电容探针测量等离子体电位的实验和方法。发射探针采用直流功率加热，并在较强电子发射条件下运行（Ｉ_（ｅ０）／Ｉ_（ｅ０）＞１）。电容探针表面二次电子发射系数δ≥１。本文对发射探针的电子发射性能、工作电流、电容探针的输入、输出电压关系进行了标定实验。得到了电容探针的校准系数分别为３×１０（－３）、５×１０（－４）。实验给出了ＭＭ－４会切中心等离子体电位Ｖ_（ｐ４）＝－８２±９－１２２±１２Ｖ；ＭＭ－４Ｕ东、西会切中心等离子体电位分别为Ｖ_（Ｐ４ｕ１）＝－５２．９±３．２Ｖ，Ｖ_（Ｐ４ｕ２）＝－６２±３．２Ｖ。     

中能原子核多重碎裂中的方位角关联

在发射源静止系碎片各向同性发射的假设条件下，考虑到碎片之间的电磁作用，研究了中能原子核多重碎裂中碎片间的方位角关联，计算结果与５００─９８０ＡＭｅＶ能区的实验数据一致．     

双盘靶等离子体运动和X光辐射

通过双盘靶实验我们观察到了等离子体的运动，运动速度小于３．５×１０７ｃｍ／ｓ；同时观测到了等离子体的会聚发射，Ｘ光的波段约在４００～７００ｅＶ之间，峰值能量在５００～６００ｅＶ之间。     

多孔硅蓝光发射与发光机制

在制备出光致发光能量为２．７ｅＶ的发射蓝光多孔硅的基础上对它进行了较系统的研究：测量了它的光致发光时间分辨光谱，用傅里叶交换红外光谱分析了其表面吸附原子的局域振动模，研究了γ射线辐照对其发光的影响，并与发红、黄光的多孔硅作了对比，通过空气中长期存放、激光和紫外线照射的方法，研究了光致发光峰能量为２．７ｅＶ的多孔硅发光稳定性．我们及其它文献中报道的多孔硅蓝光发射的实验结果与量子限制模型矛盾，但能用量子限制／发光中心模型解释．我们认为多孔硅的２．７ｅＶ发光是多孔硅中包裹纳米硅的ＳｉＯ_x层中某种特征发光中心引起的． 关键词：     

30MeV/u~(40)Ar ~(159)Tb反应中中等质量碎片的发射时标与发射机制

报道３０ＭｅＶ／ｕ４０Ａｒ＋１５９Ｔｂ反应中碎片碎片关联函数的实验结果．利用三体弹道模型从关联函数提取了中等质量碎片发射时间．中等质量碎片的平均发射时间随碎片能量而变化，从低能时的约５００ｆｍ／ｃ下降至高能时的约１００ｆｍ／ｃ．中等质量碎片发射时间随束流能量的升高而下降，表明随着束流能量的升高中等质量碎片发射机制逐渐从相继两体衰变向多重碎裂发射过渡．对于４０Ａｒ＋１５９Ｔｂ反应，此过渡能区在３５—４５ＭｅＶ／ｕ之间     

Luminescence and magnetic resonance in post-hydrogenated microcrystalline silicon

We report photoluminescence, EPR and ODMR studies of plasma hydrogenated LPCVD microcrystalline silicon thin films. Apart from the dangling bond EPR resonance which is similar to that observed in a-Si : H, and possibly the emission at 1.3 eV, we find emission bands and resonance signals quite unlike those observed in normal c-Si and a-Si : H. We conclude that μc-Si : H cannot be regarded purely as crystallites of pure silicon embedded in a matrix of a-Si : H.     

Quantum confinement in amorphous silicon quantum dots embedded in silicon nitride

Amorphous silicon quantum dots (a-Si QDs) were grown in a silicon nitride film by plasma enhanced chemical vapor deposition. Transmission electron micrographs clearly demonstrated that a-Si QDs were formed in the silicon nitride. Photoluminescence and optical absorption energy measurement of a-Si QDs with various sizes revealed that tuning of the photoluminescence emission from 2.0 to 2.76 eV is possible by controlling the size of the a-Si QD. Analysis also showed that the photoluminescence peak energy E was related to the size of the a-Si QD, a (nm) by E(eV) = 1.56+2.40/a(2), which is a clear evidence for the quantum confinement effect in a-Si QDs.     

硅微机械FP腔器件机电特性模拟

介绍了一种硅微机械FP腔器件,该器件作为光学滤波器、光学衰减器等在光纤通信技术中具有广泛应用.采用化学气相沉积、刻蚀、金属蒸发等工艺对该器件进行加工，并利用湿法腐蚀释放使其形成悬空结构，悬空膜采用静电激励驱动.分析了器件的基本原理、工作范围、静电激励的阈值电压等特性，并指出了影响阈值电压大小的因素.     

Effect of excimer laser annealing on the silicon nanocrystals embedded in silicon-rich silicon nitride film

The investigations of silicon-rich silicon nitride film grown by plasma-enhanced chemical vapor deposition and then annealed by excimer laser have been carried out systematically. The surface roughness and the crystallization of the films have significantly been improved after the excimer laser annealing. The samples demonstrate visible photoluminescence emission under optical excitation at room temperature. It is found that the emission peak energy as well as emission intensity changes with laser annealing conditions, and the relevant mechanism is discussed in detail. Our investigation exhibits the size controllability of silicon nanocrystals embedded in the silicon nitride film, which implies promising applications in optoelectronic devices such as light-emitting diodes and solar cells.     

C+注入a-SiNx：H薄膜的微结构及光发射的研究

常温下对低压化学气相沉积制备的纳米硅镶嵌结构的a-SiN_x:H薄膜进行低能量高剂量的C⁺注入后,在800~1200℃高温进行常规退火处理。X射线光电子能谱(XPS)及X射线光电子衍射(XRD)等实验结果表明,当退火温度由800℃升高到1200℃后,薄膜部分结构由SiC_xN_y转变成SiN_x和SiC的混合结构。低温下利用真空紫外光激发,获得分别来自于SiN_x、SiC_xN_y、SiC的,位于2.95,2.58,2.29 eV的光致发光光谱。随着退火温度的升高,薄膜的结构发生了变化,发光光谱也有相应的改变。     

退火温度对富硅氮化硅薄膜发光特性和结构的影响

采用直流等离子体增强化学气相沉积(PECVD)法在(100)单晶硅片表面生长富硅氮化硅薄膜,研究了不同的退火温度对氮化硅薄膜发光性质和结构的影响。研究发现,随着退火温度的升高,氮化硅薄膜的发光强度逐渐减弱,发光是由缺陷能级引起的,在900 ℃时荧光基本消失。XPS测试表明,在N₂氛围900 ℃下退火,氮化硅薄膜中未有硅相析出,故未表现出硅量子点的发光。FTIR测试也为PL结论提供了一定的证据。     

Controllable off-plane deflection of cantilevers for multiple scanning proximity probe arrays

The presented work reports the fabrication of 4×32 arrays of fully addressable proximity probes, which are initially and controllably off-plane deflected (bent). Such a deflection is required for the simultaneous approach and scanning of all cantilevers. It is realized by deposition of the silicon cantilevers with Si₃N₄ film inducing tensile stress. ANSYS simulations are used to calculate the off-plane deflection for different thickness of the cantilever and the Si₃N₄ layer and compared with experimentally obtained values. Cantilever arrays with set bending up to 50 μm, employing LPCVD silicon nitride film with a tensile stress of 750 MPa are fabricated.     

Excitonic photoluminescence characteristics of amorphous silicon nanoparticles embedded in silicon nitride film

We have investigated the photoluminescence (PL) properties of amorphous silicon nanoparticles (a-Si NPs) embedded in silicon nitride film (Si-in-SiN_x) grown by helicon wave plasma-enhanced chemical vapor deposition (HWP-CVD) technique. The PL spectrum of the film exhibits a broad band constituted of two Gaussian components. From photoluminescence excitation (PLE) measurements, it is elucidated that the two PL bands are associated with the a-Si NPs and the silicon nitride matrix surrounding a-Si NPs, respectively. The existence of Stokes shift between PL and absorption edge indicates that radiative recombination of carriers occurs in the states at the surface of the Si NPs, whereas their generation takes place in the a-Si NPs cores and the silicon nitride matrix, respectively. The visible PL of the film originates from the radiative recombination of excitons trapped in the surface states. At decreasing excitation energy (E_ex), the PL peak energy was found to be redshifted, accompanied by a narrowing of the bandwidth. These results are explained by surface exciton recombination model taking into account there existing a size distribution of a-Si NPs in the silicon nitride matrix.     

氮流量在高氢氛围中对富硅氮化硅薄膜材料结构及其发光特性的影响

采用等离子体增强化学气相沉积技术,以N₂掺入到SiH₄和H₂的沉积方式,分别在玻璃和N型单晶硅片(100)衬底上制备富硅氮化硅薄膜。通过紫外-可见光吸收光谱、傅里叶变换红外吸收光谱(FTIR光谱)、拉曼光谱和光致发光谱(PL谱)分别表征掺氮硅薄膜材料的带隙、结构及其发光特性的变化。结果表明：在氢气的氛围中,随着氮气流量的增加,氢原子能够对薄膜缺陷起到抑制作用,并使较低的SiH₄/N₂流量比下呈现富硅态,但却不利于硅团簇的形成。随着氮原子的掺入,Si—N键的含量增大,带隙增大,薄膜内微结构的无序度也增大,薄膜出现了硅与氮缺陷相关的缺陷态发光;随着氮原子进一步增加,出现了带尾态发光,进一步讨论了发光与结构之间的关联。这些结果有助于采用PECVD制备富硅氮化硅对材料发光与结构特性的优化。     

非晶碳氮纳米尖端的微结构和发光机理

利用等离子体增强热丝化学气相沉积系统,用CH₄、H₂和N₂为反应气体,在Si衬底上制备了碳氮纳米尖端。用扫描电子显微镜和显微Raman光谱仪对其进行了表征。在室温下测试了它的发光性能,发光谱由中心约为406 nm和506 nm的两条发光带组成。根据Raman散射谱,对其微结构进行了分析。结合非晶碳氮薄膜的结构和发光机理,分析了它的发光性能。