GAAS/GAALAS GRADED INDEX SEPARATE CONFINEMENT SINGLE QUANTUM-WELL SINGLE-MODE WAVE-GUIDE ELECTROABSORPTION LIGHT-MODULATOR

A GaAs/GaAlAs graded-index separate confinement single quantum well heterostructure single-mode ridge waveguide electroabsorption modulator was fabricated and investigated. For the modulator with a quantum well width of 100 angstrom and device length of 700-mu-m, an on/off ratio of 29.7 dB and estimated absorption insertion loss of 3 dB were obtained for TE polarised light with wavelength 8650 angstrom, and for TM polarisation the on/off ratio was 28.5 dB. With a switching voltage of 1 V, an on/off ratio of 15 dB was achieved. Photocurrent spectra exhibited a red shift of 600 angstrom of the absorption edge when the voltage applied to the PIN diode was varied from 0.5 to -7 V. The corresponding shift of the room temperature exciton peak energy was 96 meV.

UHV/CVD法生长硅基低位错密度厚锗外延层

采用超高真空化学气相淀积系统,以高纯Si_2H_6和GeH_4作为生长气源,用低温缓冲层技术在Si（001）衬底上成功生长出厚的纯Ge外延层.对Si衬底上外延的纯Ge层用反射式高能电子衍射仪、原子力显微镜、X射线双晶衍射曲线和Ra-man谱进行了表征.结果表明在Si基上生长的约550nm厚的Ge外延层,表面粗糙度小于1nm,XRD双晶衍射曲线和Ra-man谱Ge-Ge模半高宽分别为530″和5.5cm~(-1),具有良好的结晶质量.位错腐蚀结果显示线位错密度小于5×105cm~(-2).可用于制备Si基长波长集成光电探测器和Si基高速电子器件.

脊形结构LiNbO3光波导调制器的扩展点匹配法分析

将点匹配法扩展应用于脊形结构LiNbO3光波导调制器电极的准静态分析中.将调制器各区域的势函数表示为该区域中满足Laplace方程的一系列基函数的级数,匹配边界上有限个点的边界条件以确定出级数项的系数.通过势函数得到脊形结构LiNbO3光波导调制器结构中电场分布的解析表达式,利用求得的电场可以得到调制器特性阻抗及有效折射率.所得的特性阻抗和有效折射率与采用有限元法得到的结果十分吻合.这一分析方法简便快捷,精度高,能够处理电极有一定厚度的多层光波导调制器结构.

多孔硅膜的半峰值宽度小于10nm的针形发光峰

通过改变电化学腐蚀生成多孔硅膜的工艺条件,研究了它的发光峰形状的变化。第一次从实验上观测到多孔硅膜的针形发光激发谱和发射光谱,其半峰值宽度约小于10nm。讨论了形成针形峰的可能机理。

Effect of carrier relaxation and emission on photoluminescence of InAs quantum dots

　

Applications of dielectric thin film by electron cyclotron resonance plasma chemical vapor deposition for semiconductor photoelectronic devices

The paper reports a method of depositing SiO2, SiNx, a:Si, Si3N4 and SiOxNy dielectric thin films by electron cyclotron resonance plasma chemical vapor deposition (ECR CVD) on InP, InGaAs and other compound semiconductor optoelectronic devices,and give a technology of depositing dielectric thin films and optical coatings by ECR CVD on Laser's Bars. The experiment results show the dielectric thin films and optical coatings are stable at thermomechanical property,optical properties and the other properties. In addition, the dielectric thin film deposition that there is low leakage current is reported for using as diffusion and ion implatation masks in the paper. In the finally, the dielectric film refractive index can be accurately controlled by the N-2/O-2/Ar gas flow rate.