共查询到19条相似文献,搜索用时 78 毫秒
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采用分子束外延(MBE)方法在BaF2(111)衬底上生长了不同Mn组分的Pb1-xMnxTe(0≤x≤0.012)稀磁半导体薄膜.通过波长为3.0~11.0μm中红外透射谱的分析并应用透射光谱上干涉峰峰值的位置计算获得了Pb1-xMnxTe薄膜的折射率,由最小平方根拟合得到折射率的一阶Sellmeier色散关系.在吸收边附近,通过直接跃迁吸收系数与光子能量的关系外推得到其光学带隙.结果表明,在中红外区域其折射率随着Mn含量的增加而减小,其光学带隙则随着Mn含量的增加而增大,在温度T=295K时,随着Mn含量x由0变化到0.012,其光学带隙Eg由0.320eV增加到0.370eV. 相似文献
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文章介绍了无裂纹高导电性n型A lxGa1-xN的MOCVD生长及其电学、光学和表面形貌性质。通过A lN两步生长法,有效地解决了A lxGa1-xN外延薄膜易裂的难题。并且对其生长进行优化,减少了A lxGa1-xN外延薄膜中的受主补偿缺陷,从而实现了高导电性的n型A lxGa1-xN薄膜,其载流子浓度为4.533×1018cm-3,并且电子迁移率高达77.5cm2/V.s,已经达到了目前国际上报道的先进水平。另外光学吸收谱说明A lxGa1-xN外延薄膜在302nm处具有陡峭的带边吸收,同时结合原子力显微镜分析材料的表面形貌,证实了材料表面光滑且平整。 相似文献
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光学方法是对物理、化学、生物、医学等各种样品进行特性表征、结构和机理研究的重要方法.物体结构的细节则深藏于近场区域内,如化学和生物大分子、细胞表面的超微结构等,其大小在纳米级.常规光学方法由于受到衍射极限的限制,其最高空间分辨率只能达到波长的一半,因此无法进行研究. 相似文献
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在量子力学框架内,利用正切平方势把电子的Schrodinger方程化为了超几何方程,并用超几何函数严格求解了电子的本征值和本征函数。利用量子力学中的密度矩阵算符理论导出了正切平方势阱中的线性与三阶非线性光学吸收系数的解析表达式。计算了该系统中的线性与非线性光学吸收系数的大小,讨论了影响吸收系数变化的因素。文章以典型的AlGaAs/GaAs 势阱为例作了数值计算,数值计算结果表明,势阱的形状和入射光强对光学吸收系数的变化有着重要的影响。 相似文献
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The optical parameters for three samples of intrinsic,doped Si and doped Mg(AlxGa1-x)yIn1-yP prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model.The results obtained were discussed.The grown rates and thickness of oxidic layer on the intrinsic(AlxGa1-x)yIn1-yP surface exposed in the atmosphere were studied.Alinear dependence of oxidic layer thickness on the time was obtained. 相似文献
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用红外椭圆偏振光谱测量了室温下Hg1-xCdxTe(x=0.276,0.309,0.378)体材料位于禁带宽度之下、附近和之上的折射率。对每一种组份样品均观察到明显的折射率增强效应。折射率峰值所对应的能量位置近似等于其带宽度。禁带宽度之上折射率皮长λ变化可用Sellmeier色散关系n^2(λ)=a1 a2/λ^2 a3/λ^4 a4/λ^6进行拟合。 相似文献
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Optical properties of GaAs 总被引:2,自引:2,他引:0
We have investigated the optical properties of gallium arsenide(GaAs) in the photon energy range 0.6- 6.0 eV.We obtained a refractive index which has a maximum value of 5.0 at a photon energy of 3.1 eV;an extinction coefficient which has a maximum value of 4.2 at a photon energy of 5.0 eV;the dielectric constant,the real part of the complex dielectric constant has a maximum value of 24 at a photon energy of 2.8 eV and the imaginary part of the complex dielectric constant has a maximum value of 26.0 at a photon energy of 4.8 eV;the transmittance which has a maximum value of 0.22 at a photon energy of 4.0 eV;the absorption coefficient which has a maximum value of 0.22×108 m-1 at a photon energy of 4.8 eV,the reflectance which has a maximum value of 0.68 at 5.2eV; the reflection coefficient which has a maximum value of 0.82 at a photon energy of 5.2 eV;the real part of optical conductivity has a maximum value of 14.2×1015 at 4.8 eV and the imaginary part of the optical conductivity has a maximum value of 6.8×1015 at 5.0 eV.The values obtained for the optical properties of GaAs are in good agreement with other results. 相似文献
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Within the framework of the effective-mass approximation and the dipole approximation, considering the three-dimensional confinement of the electron and hole and the strong built-in electric field(BEF) in strained wurtzite Zn O/Mg0:25Zn0:75O quantum dots(QDs), the optical properties of ionized donor-bound excitons(D+, X)are investigated theoretically using a variational method. The computations are performed in the case of finite band offset. Numerical results indicate that the optical properties of(D+, X) complexes sensitively depend on the donor position, the QD size and the BEF. The binding energy of(D+, X) complexes is larger when the donor is located in the vicinity of the left interface of the QDs, and it decreases with increasing QD size. The oscillator strength reduces with an increase in the dot height and increases with an increase in the dot radius. Furthermore, when the QD size decreases, the absorption peak intensity shows a marked increment, and the absorption coefficient peak has a blueshift. The strong BEF causes a redshift of the absorption coefficient peak and causes the absorption peak intensity to decrease remarkably. The physical reasons for these relationships have been analyzed in depth. 相似文献
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碲镉汞体材料的显微Raman光谱 总被引:1,自引:1,他引:0
利用Raman显微镜测量了ACRT-Bridgman方法和Te溶剂方法生长的碲镉汞体材料的显微Raman光谱,在碲镉汞体材料的显微Raman光谱中识别出了碲镉汞的基本光学振动模,由此证明了碲镉汞按品格振动的分类方法属于二模混晶;识别出了一个来源于类HgTe的TO1模+LO1模的二级Raman散射峰;观察到了碲镉汞体材料中两个新的Raman散射峰,分别位于662 cm-1和749 cm-1;观察到了碲镉汞基本光学振动模的TO1模与LO1模的Raman散射强度比的变化,指出该现象是由于Raman散射几何配置不同引起的. 相似文献
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在有效质量和偶极矩近似下,考虑了由于压电极化和自发极化所引起的内建电场和量子点的三维约束效应,对纤锌矿对称Al_xGa_(1-x)N/GaN/Al_xGa_(1-x)N/GaN/Al_xGa_(1-x)N圆柱型应变耦合量子点中激子非线性光学性质进行了研究。计算结果表明,内建电场使吸收光谱向低能方向移动,发生红移现象,并且使吸收峰强度大大减小。量子限制效应使光吸收峰强度随着量子点尺寸的减小而增强,并且随着量子点尺寸的减小,吸收光谱发生蓝移现象。 相似文献