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Effect of compensation doping on the electrical and optical properties of mid-infrared type-II InAs/GaSb superlattice photodetectors 下载免费PDF全文
This paper presents a theoretical study on the electrical and optical properties of mid-infrared type-II InAs/GaSb superlattices with different beryllium concentrations in the InAs layer of the active region. Dark current, resistance-area product, absorption coefficient and quantum efficiency characteristics are thoroughly examined. The superlattice is residually n-type and it becomes slightly p-type by varying beryllium-doping concentrations, which improves its electrical performances. The optical performances remain almost unaffected with relatively low p-doping levels and begin to deteriorate with increasing p-doping density. To make a compromise between the electrical and optical performances, the photodetector with a doping concentration of 3 × 1015 cm-3 in the active region is believed to have the best overall performances. 相似文献
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A subwavelength plasmonic indented waveguide with an active InGaAsP core is proposed.The characteristics of the gap plasmon mode and gain required for lossless propagation are investigated and analyzed by the finite element method.We numerically calculate the normalized mode areas and percentages of energy confined in InGaAsP and metal for plasmonic nanolaser applications.It is shown that the indentation of the sidewalls has an optimal value for which the lasing threshold gain is minimal.The structure could enable low-threshold subwavelength lasing and applications for optoelectronic integrated circuits. 相似文献
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Theoretical analyses on improved beam properties of GaSb-based 2.X-μm quantum-well diode lasers with no degradation in laser parameters 下载免费PDF全文
An asymmetric laser heterostructure is developed to improve the beam properties of GaSb-based diode lasers with no degradation in laser parameters.Employing the semivectorial finite difference method,the dependences of beam divergence and optical confinement factor on waveguide width and refractive index step are investigated theoretically.After carefully design,a particular asymmetric laser structure is proposed.Its beam divergence in the fast axis is reduced from 61° to 34° compared with that of the broad-waveguide structure.The optical confinement factor is approximately equal to 0.0362 and comparable to that of the conventional broad-waveguide structure. 相似文献
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理论研究了平面电磁波通过n型重掺GaAs薄膜的透射谱.当GaAs薄膜两表面刻上亚波长的周期性沟槽结构时,透射谱在中红外波段出现了异常的透射增强现象.把这一现象归因于表面等离子体模式和波导模式的耦合.通过优化结构参数可以得到最大的透射效率.此外,发现随着掺杂浓度的升高,透射谱线中的透射峰逐渐向高频方向移动,最优化后透射峰值随掺杂浓度的升高而逐渐降低.这是由于掺杂浓度的改变,导致了不同的等离子体频率和电子碰撞频率,从而影响了激发模式和薄膜对电磁波的吸收.
关键词:
表面等离子体
掺杂半导体
增强透射
掺杂调制 相似文献
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Effective absorption enhancement in small molecule organic solar cells using trapezoid gratings 下载免费PDF全文
We demonstrate that the optical absorption is enhanced in small molecule organic solar cells by using a trapezoid grating structure. The enhanced absorption is mainly attributed to both waveguide modes and surface plasmon modes, which is simulated by using finite-difference time-domain method. The simulated results show that the surface plasmon along the semitransparent metallic Ag anode is excited by introducing the periodical trapezoid gratings, which induce the increase of high intensity field in the donor layer. Meanwhile, the waveguide modes result in a high intensity field in acceptor layer. The increase of field improves the absorption of organic solar cells significantly, which is demonstrated by simulating the electrical properties. The simulated results also show that the short-circuit current is increased by 31% in an optimized device, which is supported by the experimental measurement. Experimental result shows that the power conversion efficiency of the grating sample is increased by 7.7%. 相似文献