GaAlAs隐埋异质结激光器与双极晶体管的单片集成

GaAlAs隐埋异质结激光器已经和双极晶体管实现单片集成。异质结晶体管是通过激光器的掩埋层进行再生长形成的。激光器阈值电流的典型值为30mA,所获得的光电晶体管共发射极的电流增益范围为100—400。集电极电流15mA时,光电晶体管的光响应度为75A/W(响应波长为0.82μm)。     

用氧化镉(CdO)为发射区的InGaAsP/InP双异质结晶体管

本文提出和研制了一个新型的InGaAsP/InP双极型晶体管.在单片集成电路中它能与1.55μmInGaAsP/InP双异质结激光器共容而组成一个晶体管-激光器器件.该晶体管的主要特点是采用氧化镉(CdO)薄层作为器件发射区,由InP组成收集区而形成NpN双异质结晶体管.测量结果表明晶体管能双向工作,测得的正向共发射极电流增益为40(V_(CE)=5V,Ic=1mA),反向增益为8(V_(CE)=1.5V,Ic=100μA).文中还给出了h_(fe)—I_c特性和晶体管CdO-InGaAsP发射结的伏安特性.     

高光增益GaAs/Ga_(0.55)Al_(0.45)As异质结光晶体管

本文报道了具有高光增益的GaAs/Ga_(0.55)Al_(0.45)As异质结光晶体管的研制,并对影响器件光增益的一些因素作了讨论.实验中得到的最大光增益为3350.理论分析和实验结果均表明:减小基区宽度,降低基区掺杂浓度,提高基区内少子扩散长度,以及适当调整基区与发射区掺杂浓度之比将有益于提高异质结光晶体管的光增益.     

高增益异质结光电晶体管的研制

利用液相外延技术研制出高增益InGaAsP/InP异质结光电晶体管(HPT)。入射光波长为1.256μm时,实现直流光增益为88.9,微分光增益为148,光谱响应范围为0.85～1.3μm。在外偏电压小于4V时暗电流小于10nA。     

Si_(1-X)Ge_X/Si红外光电探测器

本文报导了用两种缓冲层生长技术研制的 Si1- XGe X/ Si异质结 pin型红外探测器。其波长范围为0 .70～ 1.5 5 μm,峰值波长为 0 .96～ 1.0 6 μm,暗电流密度低达 0 .0 3μA/ mm2 ( - 2 V) ,在 1.30 μm处的响应度高达 0 .15 A/ W( - 5 V) ;讨论了 Ge组分、外延层厚度、偏置电压等对探测器参数的影响     

用分子束外延生长的电流增益为1650的Al_xGa_(1-x)As/GaAs双异质结双极晶体管

制造并测试了用分子束外延(MBE)生长的AlGaAs/GaAs双异质结双极型晶体管(DHBJT)。在较宽的集电极电流范围内,基极厚度为0.2μm和0.1μm的器件,共发射极电流增益分别高达325和1650。为了获得这样高的电流增益,需要最佳化的和受控制的生长条件。这些高电流增益,与以前用分子束外延生长的晶体管所得到的最好值120相比,使异质结双极晶体管更有希望应用于低功率高速逻辑线路中。     

光通信基础知识(十四)

长波长探测器长波长探测器是指对波长1.2～1.6μm光波有良好响应的光电探测器。之所以称为“长波长”,是因为相对于0.8～0.9μm的光波来说,它的工作波长更长。在光纤通信蓬勃发展的初期,大多数光纤通信系统的工作波长都在0.85μm附近,其原因是当时光纤在0.85μm波段损耗很小,而在这一波段又有室温连续工作的AlGaAs/GaAs双异质结激光器(DHLD)以及发光二极管(LED)作光源,同时,在     

2003年IEEE国际可靠性物理年会论文集论文摘要(4)

59.200 G H z SiG e 异质结双极晶体管中雪崩电流引起的热载流子退化 (A valanche Current Induced H otCarrier D egradation in 200 G H z SiG e H eterojunctionBipolar Transistors)-- 2003 International R eliabilityPhysics Sym posium pp.339-343. 介绍了在加速雪崩应力条件下对 SiG e 异质结双极晶体管 H B T 的研究 试验中 基极-发射 ( ) , ,极结是正向偏压 收集极-基极结是反向偏压 处 , ,于雪崩条件下 高能雪崩载流子 热载流子 给 。 …     

超高速化合物半导体器件(6)

以高电子迁移率晶体管、异质结双极晶体管和微波/毫米波集成电路为例,介绍化合物半导体器件的特点、封装、测试及其应用.     

InGaAsP/InP波长可选异质结光电晶体管

采用InGaAsP/InP材料系,将吸收层加到宽带隙异质结光电晶体管上,研制出了具有窄光谱响应的高增益光电晶体管(波长可选光电晶体管)。得到了光谱响应峰值约1.2μm,光谱半宽度为53μm。在峰值波长和入射光功率P_(in)为3.6μw时,这种器件呈现出高达400的光学增益。在P_(in)=10μw时,测得上升时间是18μs。还测量了器件的噪声特性,在光学偏置功率为0.1μw、频率为2 KHz时,估计器件总探测度为3.7×10~(10)cm·Hz~(1/2)/W。从理论上详细讨论了这些特性。     

Theoretical studies of poly(para-phenylene vinylene) (PPV) and poly(para-phenylene) (PPP)

The electroluminescence from PPV and the blue light emission from PPP constitute exciting subjects of study. The band gap of these semiconducting polymers can be engineered in a wide range from red to ultraviolet by structural changes made on them. In the present work, we present a theoretical approach based on semiempirical and ab initio total energy and force calculations of PPV and PPP. We perform a conformational analysis in order to investigate the connection between their structural, optical and electronic properties. We use the large cell approach, in connection with the semiempirical quantum method Extended Hückel (BICON-CEDiT code) and the density functional theory (DFT) within the full-potential linearized augmented-plane-wave method (FPLAPW) as implemented in the computational code WIEN2k. Our results are compared to other calculations and to optical absorption measurements.     

(Sr_(0.5)Ba_(0.5))_(1.9)Ca_(0.1)NaNb_(5–x)TaxO_(15)陶瓷的介电性能

通过Ta掺杂改性钨青铜陶瓷(Sr0.5Ba0.5)1.9Ca0.1NaNb5–xTaxO15(x=0～0.30),分析了Ta掺杂量对其烧结性能、微观结构及介电性能的影响。陶瓷的烧结温度随x的增大略有提高。当x<0.10时,陶瓷的tC和弛豫性变化不大;当x≥0.10时,tm(1kHz)明显降低,从270℃(x=0)降低至231℃(x=0.30)。且tm随频率增加向高温移动,弛豫性明显增强。认为Ta掺杂引起其性能变化是由于Ta—O键与Nb—O键键能的差异,导致陶瓷氧八面体中心离子位移量以及A位离子有序程度的变化所致。     

纳米复合(Nd,Pr)FeTiBC永磁合金的结构与磁性能

采用熔体快淬法制备了纳米复合(Nd1-xPrx)9.4Fe75.6Ti4B10.5C0.5(x为0,0.2,0.4,0.6,0.8和1.0)合金薄带,研究了Pr对合金薄带结构与磁性能的影响规律。结果表明:Pr降低了合金薄带的晶化温度,使合金薄带晶粒变得粗大,不利于合金矫顽力的提高。Pr对合金薄带磁性能的影响不大,不同Nd和Pr比例的合金薄带在最佳热处理条件下,剩磁Br在0.86 T与0.90 T之间,内禀矫顽力Hcj在1 000 kA/m左右,最大磁能积(BH)max介于130 kJ/m3与136 kJ/m3之间。     

Miniband spectra of (AlAs)M(GaAs)N(111) superlattices

Semiconductors - Electron states in the conduction band of (111)-oriented (AlAs)M(GaAs)N superlattices (SLs) with M≥N and N&;lt;10 are considered. The properties of such SLs are mainly...     

单层超晶格Ga_(0.47)In_(0.53)As/InP(110)及半导体合金Ga_(0.235)In_(0.765)P_(0.5)As_(0.5)的状态密度及介电常数(英文)

The DOS, JDOS and ε2(Ω) of monolayer superlattice Ga0.47ln0.53As/ InP(110) have been calculated by a tight-binding approach and compared with that of alloy Ga0.235ln0.765P0.5As0.5 which has the same stoi-chiometric composition as the monolayer superlattice. By using the techniques of the group theory we have obtained the expressions of momentum matrix elements between valence band states and conduction band states with four adjustable parameters. These parameters are determined by fitting the calculated values of ε2(Ω) with the experimental values for InP, GaAs and InAs. Our results show that the superlattice periodicity makes its DOS, JDOS and ε2(Ω) different from those of alloy in varying degree. Due to the folding of Brillouin zone, the JDOS of superlattice turns round in comparison with that of alloy. The momentum matrix elements have different effects for the superlattices and alloys.For the alloys, they can only change the amplitudes of peaks but not the positions of peaks; however, for the superlattices both amplitude and position can be changed.     

Sr_(0.3)Ba_(0.7)Bi_(3.7)La_(0.3)Ti_4O_(15)铁电陶瓷的烧结及介电性能

采用两步烧结工艺制备Sr0.3Ba0.7Bi3.7La0.3Ti4O15铁电陶瓷,研究了烧结工艺对陶瓷的晶相和介电性能的影响。结果表明:适当提高最高温度、保温温度和保温时间可改善陶瓷的介电性能。当最高温度为1180～1200℃,在1050～1080℃保温5～15h时,其εr为238～262,tanδ小于10–2,σ为1.0×10–11～10–12S·m–1。该烧结工艺可减少铋的挥发,降低氧空位浓度,因而减弱了陶瓷的高温低频耗散现象。随着保温时间的增加,高温电导得到有效抑制,在1050℃保温15h样品的σ降低了一个数量级,在280℃时为5.2×10–9S·m–1。     

Electron-phonon interaction in short-period (GaAs) m (AlAs) n (001) superlattices

The deformation potentials of electron scattering at short-wavelength phonons for intervalley transitions in the conduction band of short-period (GaAs) _m (AlAs) _n (001) (m, n = 1, 2, 3) superlattices are determined by the electron density functional method. The dependences of the electron and phonon states and deformation potentials on the layer thickness in the superlattices are analyzed. The results of ab initio calculations are in good agreement with the data of empirical calculation of the deformation potentials integrated over phonons, but differ from data on the corresponding potentials for partial scattering channels because of approximations of the phenomenological model of interatomic binding.     

全球信息基础设施总体概念问题(上)

本文讨论了电信技术、网络形态和发展电信技术的指导思想,目的是从技术机理和工程应用方面说明GII网络形态的总体概念.     

复合量子阱Ge_(0.3)Si_(0.7)/(Ge_(0.3)Si_(0.7))_m-(Si)_m/Ge_(0.3)Si_(0.7)的电子能带结构

采用建立在经验赝历势基础上的推广k·P方法计算了复合量子阱Ge0.3Si0.7／（Ge0.3Si0.7）m-（Si）m／Ge0.3Si0.7的电子束缚能组及其活界面方向的色激关系,并与通常的单带模型下的包络函数方法的计算结果进行了比较。结果表明由于超晶格中子能带的形成,邻近能带间的互作用使通常单带模型下的包络函数方法不再能适用于复合量子阱的计算。计算结果也表明复合量子阱的电子束缚能级沿界面方向在kx＜0.1（2π/a）范围内基本上不随kx变化。     

sol-gel法制备Ba_(3.99)Sm_(9.34)Ti_(18)O_(54)微波介质陶瓷

以柠檬酸为络合剂,通过sol-gel法制备了Ba3.99Sm9.34Ti18O54陶瓷前驱体;经1100℃预烧2h压片成型后,再在1300℃保温3h,即得到了烧结致密的陶瓷样品。与传统固相法相比,其烧结温度降低了50℃,且陶瓷晶粒细小,晶粒分布均匀,具有更加优良的微波介电性能:εr=79.56,Q·f=9636GHz(4.71GHz),τf=–1.23×10–6/℃。