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通常利用Hall系数的测量确定半导体材料的掺杂浓度。我们认为,对Si:In:而言,这样测量的结果误差大。用曲线拟合法测出的Hall浓度是利用直接测量掺杂浓度的C—V及结击穿法测得的浓度的两倍。我们认为后者的数据更可靠些。 相似文献
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离子注入硅片经高温退火后晶体结构缺陷会被修复,其在可见光波段下的光学性质趋于单晶硅,常规的可见光椭偏光谱法对掺杂影响的测量不再有效.本研究将测量波段扩展到红外区域(2—20μm),报道了利用红外椭偏光谱法测量经离子注入掺杂并高温退火的硅片掺杂层光学和电学性质的方法和结果.通过建立基于Drude自由载流子吸收的等效光学模型,得到了杂质激活后掺杂层的杂质浓度分布、电阻率和载流子迁移率等电学参数,以及掺杂层的红外光学常数色散关系,分析了这些参数随注入剂量的关系并对其物理机理给予了解释.研究表明,中远红外椭偏测量是表征退火硅片的有效方法,且测量波长越长,所能分辨的掺杂浓度越低. 相似文献
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分析了影响金刚石膜热导率的主要因素,指出声子的散射是造成金刚石膜热导率降低的主要原因.采用光热偏转法实现了金刚石薄膜热导率的测试,测量误差小于5%,从减少杂质和晶界对导热声子的散射入手,研究了在不同的制备方法下碳源气体和金刚石膜内晶粒取向对其热导率的影响.结果表明在低碳源气体浓度下采用微波等离子体化学汽相沉积方法制备的具有较高程度(400)晶粒取向的金刚石薄膜具有高的热导率性质.优化的工艺条件制备出热导率为15.2W/(K·cm)左右的金刚石膜.
关键词: 相似文献
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Yb:YAG晶体的热学性质及其对激光性能的影响 总被引:2,自引:1,他引:1
对于中频感应加热提拉法(Czochralski Method)生长的高掺杂浓度(原子数分数0.30)Yb:YAG晶体,经退火后采用差示扫描量热计法测量了晶体的比热容,通过激光脉冲法测量了不同掺杂浓度(原子数分数0.05-0.30Yb:YAG晶体的热扩散率和热导率。实验表明,随着Yb^3 离子浓度增加,Yb:YAG晶体在300K温度下的导热性能有明显的降低。原子数分数为0.30的Yb:YAG晶体的激光实验表明,高掺杂浓度Yb:YAG晶体热导率的降低导致了激光阈值的增加。 相似文献
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光热膨胀材料的光谱特性是影响微型光热驱动机构性能的关键因素,该文在理论分析的基础上,采用单积分球测量法对四种聚合物材料的反射光谱及吸收特性进行了实验测量,据此选择制作光热驱动机构的最佳光热膨胀材料,发现掺杂染料的高密度聚乙烯(HDPE)材料在600~690 nm的范围内有较强烈的吸收.选取HDPE作为光热膨胀材料,设计制作了一种长度1 500 μm的微型光热驱动机构,并采用自行研制的CCD显微监控和视频运动测量系统进行了驱动机构的驱动性能测量实验.研究结果表明,在10 mW/650 nm的半导体激光器驱动下,该微型光热驱动机构可以产生18.7 μm的光热偏转量,说明其具有良好的光谱吸收和光热转换特性,可望在微光机电系统(MOEMS)中获得广泛应用. 相似文献
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阐明了3ω方法的机理,并在此基础上讨论了它的一些基本应用.利用3ω方法可以对具有优 良导热和导电能力的材料的热导率和热容进行测量;对不能导电的材料,固态的或液态的, 利用3ω方法能对它们的热导率进行测量.对测量中涉及到的热辐射问题的讨论表明,由于使 用的是小样品,热辐射造成的影响可以忽视.通过理论推导,使用二维隧穿结点阵并借助3ω 方法,可以给出一种性能良好的二维库仑阻塞测温法.
关键词:
3ω方法
热容(定压)
热导率
库仑阻塞 相似文献
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For thermal conduction cases,one can detect the size of an object explicitly by measuring the temperature distribution around it.If the temperature is the only signature we can obtain,we will give an incorrect judgment on the shape or size of the object by disturbing the distribution of it.According to this principle,in this article,we develop a transformation method and design a dual-functional thermal device,which can create a thermal illusion thai the object inside it"seems"to appear bigger or smaller than its original size.This device can functionally switch among magnifier and minifier at will.The proposed device consists of two layers:the cloak and the complementary material.A thermal cloak can make the internal region thermally"invisible"while the complementary layer offsets this effect.The combination leads to the illusion of magnification and minification.As a result of finite element simulations,the performances of the illusions are confirmed. 相似文献
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P.J.A. Sazio J.H. Thompson G.A.C. Jones E.H. Linfield D.A. Ritchie M. Houlton G.W. Smith 《Superlattices and Microstructures》1996,20(4):535-544
Conventional molecular beam epitaxial (MBE) growth of III-V semiconductor material systems use a thermal silicon effusion cell as the n-type dopant source. In the technique described here, the thermal source is replaced with a scanning Si focused ion gun. It is therefore possible to directly write dopant patterns into the semiconductor waferit as it is being grown. The precise control over the elemental composition in the growth (z) direction permitted by MBE, combined with high spatial resolution of the focused dopant ion beam in the lateral (xy) plane, allows direct registration of fully integrated, three-dimensional semiconductor structures and devices otherwise unobtainable via conventional lithographic techniques. In this paper, we present electrical measurements of high mobility GaAs/AlGaAs modulation doped heterostructures fabricated using this technique.Fabrication of novel undoped channel FET structures is also discussed, where the dopant beam is used to form extended contacts to the induced electron gas. FET action is demonstrated for the first time using this technique, eliminating the constraint for self-alignment in undoped structures. 相似文献
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Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of the least square boundary collocation technique. The distribution of thermal stress for the functionally graded interphase layer with arbitrary radial material parameters is derived by using the method of piece-wise homogeneous layers when the finite matrix is subjected to uniform heat flow. The effects of matrix size, interphase thickness and compositional gradient on the interfacial thermal stress are discussed in detail. Numerical results show that the magnitude and distribution of interfacial thermal stress in the inclusion and matrix can be designed properly by controlling these parameters. 相似文献
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Determining the thermophysical properties of Al-doped ZnO nanoparticles by the photoacoustic technique 下载免费PDF全文
The thermal conductivity and specific heat capacity of undoped and Al-doped (1-10 at.%) ZnO nanoparticles prepared using the solvent thermal method are determined by measuring both thermal diffusivity and thermal effusivity of a pressed powder compact of the prepared nanoparticles by using the laser-induced photoacoustic technique. The impact of Al doping versus the microstructure of the samples on such thermal parameters has been investigated. The results reveal an obvious enhancement in the specific heat capacity when decreasing the particle size, while the effect of Al doping on the specific heat capacity is minor. The measured thermal conductivities are about one order of magnitude smaller than that of the bulk ZnO due to several nested reducing heat transfer mechanisms. The results also show that Al doping significantly influences the thermal resistance. Using a simple thermal impedance model, the added thermal resistance due to Al dopant has been estimated. 相似文献
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Sh. A. Kalmykov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2017,11(2):371-374
A method for determining the depth distribution of ion-implanted impurity atoms in semiconductors is developed. The method consists in measuring the concentration of impurities by X-ray fluorescence analysis upon the ellipsometry controlled removal of thin semiconductor layers. It is found that the prolonged low-energy X-ray radiation exposure of an ion-implanted semiconductor layer leads to a change in the distribution profile of the ion-implanted impurity atoms. 相似文献
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采用激光光热透射技术测量材料的热扩散率 总被引:2,自引:0,他引:2
介绍利用激光光热透射技术测量材料热扩散率的方法,用该方法测量黄铜,纯铁、铝、纯铜及锗的热扩散率,其结果与能常采用的检测手段一致。 相似文献
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A. Cruz Orea I. Delgadillo H. Vargas J.L. Pichardo J.J. Alvarado-Gil L.C.M. Miranda 《Solid State Communications》1996,100(12):855-859
The photoacoustic technique is used in semiconductor two-layer systems for the determination of thermal properties and thermal expansion coefficient. The two-layer systems studied were amorphous silicon-glass and Al0.2Ga0.8As---GaAs. Our results show that the proposed method is a reliable technique for the characterization of other semiconductor two-layers systems. 相似文献
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将单层二硫化钼用石墨烯进行封装,构造了石墨烯和二硫化钼的范德瓦耳斯异质结构,并且分别在氩气(Ar)和氢气(H2)氛围下,详细研究了被封装的二硫化钼的热稳定性.结果表明:在氩气氛围中,石墨烯封装的二硫化钼在400–1000℃下一直保持稳定,而石墨烯和氧化硅上裸露的二硫化钼在1000℃时几乎全部分解;在氢气氛围中,石墨烯封装的二硫化钼在400–1000℃下一直稳定存在,而石墨烯和氧化硅上裸露的二硫化钼在800℃下已经完全分解.综上可得,在氩气和氢气的氛围下,被石墨烯封装的二硫化钼的热稳定性得到了显著的提高.该研究通过用石墨烯将单层的二硫化钼进行封装以提高其热稳定性,在未来以单层二硫化钼作为基础材料的电子器件中,可以保证其在高温下能够正常工作.该研究也为提高其他二维材料的热稳定性提供了一种可行的方法和思路. 相似文献