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集中讨论 MCT 光导芯片电阻率随时间变化的问题。研究结果表明:MCT芯片中 Hg 原子的逐渐逸出导致了材料组分即 x 值随时间变化,这是芯片室温电阻率变化的主要原因;另外,在某些条件下(如加温),芯片表面可形成高浓度的 n 型载流子薄层,也将引起芯片的室温电阻率的变化。 相似文献
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测定了室温下Na5TbxEu1-x(MoO4)4的发射光谱。发现随x的增加,Tb^3+离子546nm(^5D4→^7F5)的荧光发射亦随这增加。同时观察到,当x>0.7时,发光相对强度变化会出现突变。 相似文献
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SPRITE探测器的电阻是一个重要的器件参数。研究了Hg1-xCdxTe材料组分和电阻率、芯片厚度和表面电导等因素对该电阻的影响,并就实验数据进行了比较结果表明:SPRITE器件的室温电阻主要是受Hg1-xCdxTe材料组份和芯片厚度的影响。而其液氮温度电阻则主要是受芯片表面电导的影响。 相似文献
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用分子束外管生长了不同组分x的Zn1-xMnxSe外延膜和Zn1-xMnxSe/ZnSe超晶格,由于Zn1-xMnxSe的能隙Eg随组分变化在爸组分区形成弓形,且弓形的范围随温度变化的反常特性,首次在光致发光谱(PL)中观测到当温度升高时,Zn1-xMnxSe/ZnSe超晶格中由ZnSe为阱、Zn1-xMnxSe为垒转换成Zn-1xMnxSe为阱,ZnSe为垒,瞬态光致发光结果表明,Zn1-xMn 相似文献
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用分子束外延生长了不同组分x的Zn1-xMnxSe外延膜和Zn1-xMnxSe/ZnSe超晶格.由于Zn1-xMnxSe的能隙Eg随组分变化在低组分区形成弓形,且弓形的范围随温度变化的反常特性,首次在光致发光谱(PL)中观测到当温度升高时,Zn1-xMnxSe/Znse超晶格中由ZnSe为阱、Zn1-xSe为垒转换成Zn1-xSe为阱,ZnSe为垒.瞬态光致发光结果表明,Zn1-xMnxSe/ZnSe超晶格中Mn++离子的激发态弛豫时间远大于Zn1=xMnxSe外延模中Mn++离子的弛豫时间,这可能是由于 相似文献
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本文计算了闪锌矿结构Zn(1-x)MnxSe光学声子频率随组分x值的改变.计算表明,Zn(1-x)MnxSe混晶的光学声子属混模行为.在计算中,表征晶格常数改变对力常数影响的物理量,不同混晶应取不同的值. 相似文献
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测定了室温下Na5ThxEu1-x(MoO4)4的发射光谱。发现随x的增加,Tb3+离子546nm(5D4→7F5)的荧光发射亦随之增加。同时观察到,当x>0.7时,发光相对强度变化会出现突变。被认为是由于Tb3+离子中存在5D3能级向5D4能级进行无辐射共振能量转移所致。 相似文献
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本文计算了闪锌矿结构Zn1-xMnxSe光学声子频率随组分X值的改变,计算表明,Zn1-xMnxSe混晶的光学声子属混模行为,在计算中,表征晶格常数改变对力常数影响的物理量,不同混晶应取不同的值。 相似文献
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音处理、中低速语音编码研究,在国内外重要期刊、会议上发表论文多篇。TMS320C2××(以后简称为C2x×)是德克萨斯仪器公司最新生产的一种高效、廉价的定点数字信号处理芯片。这类芯片的处理能力可达到40MIPS,而且成本特别低。TI公司生产了C1x,C2x,C5x三代定点数字信号处理芯片。其中C1×的处理能力是5MIPS,C2×的处理能力是10MIPS,C5×的处理能力是40MIPS。C1×系列早期应用比较多,目前的应用已经不多;C2x的主要优点是廉价,成本低,但相对于C5x而言它的主要缺点是处… 相似文献
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The thermoelectric properties of n-type Hg0.79Cd0.21Te (MCT) and of MCT layers with n-p structure have been investigated in transverse (B ⊥ ∇T) and longitudinal (B ‖∇T) magnetic
fields (0 ≤ B ≤ 16 kG) using the lateral gradient method at temperatures between 10 and 300K. The experimental results were
analyzed by considering the contributions of electrons and holes to the magneto-thermoelectric effect and the scattering mechanisms
involved. The analysis is based on a nonparabolic conduction band and Landau quantization as well as empirical relations for
the band gap, the intrinsic carrier density, and the magnetoresistance. For n-type MCT at low temperatures (10 < T < 30K)
and weak magnetic fields (B < 2 kG), the transverse magneto-thermoelectric effect (TME) was seen to be dominated by electron
scattering on ionized defects. Longitudinal acoustic phonon drag was found to affect the TME in strong magnetic fields (B
> 3 kG) at low temperatures (T < 20K). Longitudinal (LO) phonons were shown to prevail in the electron scattering at higher
temperatures (T > 50K) in weak magnetic fields. With increasing magnetic fields, the effect of LO-phonon scattering decreases,
and eventually the TME becomes independent of electron scattering. The longitudinal magneto-thermoelectric effect of n-type
MCT was also found to exhibit magnetophonon oscillations due to LO-phonon scattering from both HgTe and CdTe phonons. The
transverse magnetoresistance (TMR) of the n-type layers in the quantum region has been found to be linearly dependent on the
magnetic field. Owing to the TMR of the n-type layers, the variation of the TME of p-n multiple layers with magnetic field
is much larger than the variation of the Seebeck coefficient with temperature. Thus, the sensitivity to p-type layers is considerably
enhanced compared to that of the Seebeck coefficient. As a result, the TME has proved to be particularly useful in determining
the doping and composition of the constituent layers of MCT n-p structures. 相似文献
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通过求解Poisson方程,对热平衡态金属:p-n-CdTeSchotky势垒薄膜太阳能电池进行计算机数值模拟。嵌入的p型层增大传统金属:n-CdTe结的有效Schotky势垒高度与p型层厚度、掺杂浓度以及n-CdTe本底电阻率有依赖关系。最后讨论嵌入p型层增强CdTeSchotky势垒太阳能电池对光生载流子的收集作用。 相似文献
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C. H. Swartz R. P. Tompkins N. C. Giles T. H. Myers D. D. Edwall J. Ellsworth E. Piquette J. Arias M. Berding S. Krishnamurthy I. Vurgaftman J. R. Meyer 《Journal of Electronic Materials》2004,33(6):728-736
Variable magnetic-field Hall and transient photoconductance-lifetime measurements were performed on a series of undoped, In-doped,
and As-doped HgCdTe samples grown by molecular beam epitaxy (MBE). Use of quantitative mobility-spectrum analysis (QMSA) combined
with multiple carrier-fitting (MCF) techniques indicates that the majority of samples contain an interfacial n-type layer
that significantly influences the interpretation of the electrical measurements. This n-type layer completely masks the high-quality
electrical properties of undoped or low n-type In-doped HgCdTe, as well as complicating the interpretation of activation in
As-doped p-type HgCdTe. Introduction of an intentional n-type background, typically created through doping with In to “recover”
high mobility, is actually shown to increase the “bulk” layer conductivity to a level comparable to the interface layer conductivity.
Photoconductance-lifetime measurements suggest that In-doping may introduce Shockley-Read-Hall (SRH) recombination centers.
Variable-field Hall analysis is shown to be essential for characterizing p-type material. Photoconductance-lifetime measurements
suggest that trapping states may be introduced during the incorporation and activation of As. Two distinctly different types
of temperature dependencies were observed for the lifetimes of As-doped samples. 相似文献
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报道了碲镉汞p+-on-n长波双层异质结材料和异质结台面器件的研究结果,重点研究了p+-on-n型双层异质结材料制备技术。通过水平滑舟富碲液相外延生长的方法在碲锌镉衬底上原位生长In掺杂碲镉汞n型吸收层材料,然后再采用富汞垂直液相外延技术制备p型As原位掺杂的碲镉汞cap层材料,从而获得p+-on-n型双层异质结材料,并通过湿法腐蚀、台面刻蚀以及钝化等工艺得到碲镉汞 p+-on-n长波异质结台面型器件。p+-on-n异质结器件结构可以有效克服少子寿命偏低等问题,在长波及甚长波波段具有更低的暗电流和更高的R0A值,这对于解决目前长波碲镉汞红外探测器暗电流大、结阻抗低的问题,提高长波及甚长波波段碲镉汞红外焦平面器件的性能具有重要的意义。 相似文献
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碲锌镉晶体中存在着各种典型晶体缺陷,其缺陷研究一直倍受关注,X射线衍射形貌术是一种非破坏性地研究晶体材料结构完整性、均匀性的有效方法.采用反射式X射线衍射形貌术对碲锌镉衬底的质量进行了研究,并将衬底的X射线衍射形貌与Everson腐蚀形貌进行了对比分析,碲锌镉衬底的X射线衍射形貌主要有六种特征类型,分别对应不同的晶体结构或缺陷,包括均匀结构、镶嵌结构、孪晶、小角晶界、夹杂、表面划伤,对上述特征类型进行了详细的分析.目前,衬底的X射线衍射形貌主要以均匀结构类型为主,划伤和镶嵌结构缺陷基本已消除,存在的晶体缺陷主要以小角晶界为主.通过对比分析碲锌镉衬底和液相外延碲镉汞薄膜的X射线衍射形貌,发现小角晶界等晶体结构缺陷会延伸到外延层上,碲锌镉衬底质量会直接影响碲镉汞外延层的质量,晶体结构完整的衬底是制备高质量碲镉汞外延材料的基础. 相似文献
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采用化学和物理方法分别在Hg1-xCdxTe (MCT)表面制备了阳极氟化膜、CdTe、ZnS和类金刚石薄膜(DLC)钝化层.采用俄歇光谱(AES)和红外透射光谱(IR)研究了这些钝化层与MCT之间的界面特性.结果表明与阳极氟化膜和CdTe膜相比,ZnS和DLC膜能较好地抑制MCT组元的外扩散.ZnS层中的Zn和S 易于向MCT内部扩散,而且发现在ZnS层中有O的存在,这可能是由于ZnS易与空气中水份发生作用所致.而DLC中C向MCT内表面扩散较少.MCT表面沉积DLC薄膜后红外透过率较ZnS有明显的提高. 相似文献