一种基于能带工程设计的CaAsSb/InP异质结双极晶体三极管

异质结晶体三极管（HBT）的性能与其材料体系密不可分，利用能带工程可以大大优化器件的结构，提高器件性能，文章从分析HBT的能带结构及设计要求入手，介绍了一种利用能带工程设计的基于GaAsSb/InP材料体系的新型HBT器件的结构及其性能，分析了该器件与其它材料体系器件相比所具有的优异特性，说明了对HBT的各区材料，其带边的相对位置所起的重要作用，最后，文章还报道了近期的实验情况，说明了GaAsSb/InP体系HBT的实际性能与理论预言一致。     

Γ andX bandgap hydrostatic deformation potentials for epitaxial In0.52Al0.48As on InP(001)

The pressure dependence of the direct and indirect bandgap of epitaxial In_0.52Al_0.48As on InP(001) substrate has been measured using photoluminescence up to 92 kbar hydrostatic pressure. The bandgap changes from Γ toX at an applied pressure of ∼ 43 kbar. Hydrostatic deformation potentials for both the Γ andX bandgaps are deduced, after correcting for the elastic constant (bulk modulus) mismatch between the epilayer and the substrate. For the epilayer we obtain and+(2.81±0.15)eV for the Γ andX bandgaps respectively. From the pressure dependence of the normalized Γ-bandgap photoluminescence intensity a Γ-X lifetime ratio, (τ_Γ/τ _X ), of 4.1×10⁻³ is deduced.     

The recent progress of wide bandgap donor polymers towards non-fullerene organic solar cells

The recent progress of wide bandgap (WBG) donor polymers for non-fullerene polymer solar cells (NF-PSCs) were reviewed in detail, which was classified by D-type and D-A type molecular backbones to discuss the related structure-property correlations and put forward an outlook for future innovations.     

一种新型双层PBG结构带阻滤波器

本文介绍了一种双层结构的基于村底打孔的PBG结构带阻滤波器，采用了周期结构与微带电路分离的设计。解决了传统的打孔结构的导带加工问题，并且有利于电路的加工和修改。最后给出了利用HFSS理论仿真和实际测量的结果，论证了这种结构的可行性     

晶态纳米纤维素的多色圆偏振荧光性能

基于晶态纳米纤维素禁带效应的圆偏振荧光能力,分别采用混合悬浮液法及多层膜叠加法拓宽了晶态纳米纤维素膜的禁带,使其禁带覆盖可见光范围,通过掺杂多色荧光体,该膜可以将自发辐射转换为高强度、右旋、多色的圆偏振荧光信号.     

吸收对对称性一维三元光子晶体能带的影响

利用复折射率及传输矩阵理论,研究了光子晶体的吸收对对称性一维三元光子晶体能带及透射峰的影响,研究表明:在反射波中,禁带的反射率随消光系数的增加而迅速降低,当k增加到0.005时,禁带边缘模糊,不存在明显的禁带;在透射波中,随着消光系数的增大,禁带边缘逐渐模糊,当k增加为0.003时,透射率降为0.35;光子晶体的消光系数对禁带内透射峰的透射率有着明显的影响,当k为0.001时,透射率下降到0.15,随着消光系数的增加,透射峰的半峰全宽随之增加,但对透射峰的中心波长没有影响.     

通讯波段禁带胶体光子晶体的制备及实验参数研究

采用直径为700nm的二氧化硅微球,通过垂直沉积法在玻璃基片上制备了位于光通讯波段的禁带胶体光子晶体。研究了不同蒸发温度、湿度条件、干燥过程对样品晶体质量的影响。用扫描电子显微镜(SEM)对其形貌进行了观测。实验结果表明,在温度为65℃,相对湿度为70%,缓慢干燥条件下制备出的样品具有较好的晶体质量,晶体在大范围内保持了面心立方(FCC)单晶结构,其(111)面平行于生长基片。     

Novel 1-D Sandwich Photonic Bandgap Structure

A sandwich photonic bandgap (PBG) structure is a novel PBG structure whose periodic lattice is buried in the middle of a substrate. Neither drilling nor suspending the substrate is required, and the integrity of the ground plane is maintained. This paper presents several modification techniques for sandwich PBG structure fabrication. The forbidden gap can be improved by adopting the chirping technique, applying the tapering technique, enlarging the periodic elements, adjusting the location of the periodic lattice in the substrate, and using different dielectric media H-shape elements. A finite difference time domain method is applied to analyze the structures. Deep and wide stopbands can be obtained using the modified sandwich structures. Experimental measurement results agree well with the theoretical analysis.     

采用分段曲率补偿的新型带隙基准电压源设计

设计了一种利用MOS晶体管产生正负温度系数电流的新型带隙基准电压源,并采用分段曲率补偿技术,从而降低基准电压的温度系数,同时增加工作温度范围.该电路使用TSMC 0.6 um标准CMOS工艺进行设计,Spectre仿真结果表明,电源电压为1.5 V,温度范围为-15~95℃时,温度系数为107 ppm/℃,采用分段曲率补偿后,温度系数降为4.28 ppm/℃.     

Indandione-Terminated Quinoidal Compounds for Low-Bandgap Small Molecules with Strong Near-Infrared Absorption: Effect of Conjugation Length on the Properties

Low-bandgap organic semiconductors have attracted much attention for their multiple applications in optoelectronics. However, the realization of narrow bandgap is challenging particularly for small molecules. Herein, we have synthesized four quinoidal compounds, i. e., QSN3 , QSN4 , QSN5 and QSN6 , with electron rich S,N-heteroacene as the quinoidal core and indandione as the end-groups. The optical bandgap of the quinoidal compounds is systematically decreased with the extension of quinoidal skeleton, while maintaining stable closed-shell ground state. QSN6 absorbs an intense absorption in the first and second near-infrared region in the solid state, and has extremely low optical bandgap of 0.74 eV. Cyclic voltammetry analyses reveal that the lowest unoccupied molecular orbital (LUMO) energy levels of the four quinoidal compounds all lie below −4.1 eV, resulting in good electron-transporting characteristics in organic thin-film transistors. These results demonstrated that the combination of π-extended quinoidal core and end-groups in quinoidal compounds is an effective strategy for the synthesis of low-bandgap small molecules with good stability.