HEMT结构材料中二维电子气的输运性质研究

该文通过变温的Hall测量系统地研究了GaAs基HEMT和PHEMT以及InP基HEMT三种结构材料的电子迁移率μ_n和二维电子浓度n_s。仔细地分析了不同HEMT结构材料的散射机制对电子迁移率的影响以及不同HEMT材料结构对电子浓度的影响。研究结果表明InP基HEMT的n_s×μ_n值比GaAs基HEMT和PHEMT的n_s×μm值都大，说明可以用n_s×μ_0值来判断HEMT结构材料的性能好坏。

二氧化硅覆盖退火增强磷化铟基体激光器材料的量子阱混合

对SiO_2覆盖退火增强InGaAs/InGaAsP/InP激光器材料量子阱混合技术进行了实验研究。相对于原始样品，退火时无SiO_2覆盖的样品经800℃，30s快速退火后，其光致发光谱的峰值波长“蓝移”了7nm,退火时有SiO_2覆盖的样品经过同样的快速退火后，其光致发光谱的峰值波长“蓝移”了56nm。即在同一片子上实现了在需要量子阱混合的区域带隙的“蓝移”足够大的同时，不希望量子阱混合的区域能带结构的变化创记录的大小。该文认为增大量子阱的宽度、采用无应力的量子阱结构以及引入足够厚的缓冲层可以改善量子阱材料的晶格质量，有利于提高量子阱混合技术的可靠性与重复性，改善量子阱材料的热稳定性。

InGaAs/InAlAs多量子阱电吸收光调制器

用国产MBE设备生长出与InP衬底晶格匹配的InGaAs/InAlAs多量子阱材料，并对材料的量子限制Stark效应及其与光偏振方向有关的各向异性电吸收特性进行研究。用该种材料制作的脊波导结构电吸收调制器在2.4V驱动电压下实现了20dB以上消光比，光3dB带宽达3GHz。

InGaAs/InAlAs多量子阱结构的量子限制Stark效应研究

通过吸收光电流谱的测量,观察到用国产MBE设备生长的与InP衬底晶格匹配的InGaAs/InAlAs多量子阱结构的量子限制Stark效应及其与光偏振方向有关的各向异性电吸收特性,报道了可用于波导型调制器制作的MQW样品材料的X射线双晶衍射结果,并用计算机模拟出与实测十分相似的曲线,得到了可靠的量子阱结构,证明样品材料具有优良的外延质量.利用等效无限深阱模型进行的理论计算表明,应考虑样品p-i-n结内建电场的影响,才能使算出的吸收边红移与实验值符合.

氧离子注入隔离的全内反射型光波导开关

研制了一种全内反射型InGaAsP/InP光波导开关。采用氧离子注入形成的高阻特性来作为载流子注入区的隔离。由此获得陡峭的反射面,改善了光开关的性能。在入射光波长为1.3 μm,注入电流为32 mA下得到光开关反射端消光比为18 dB,无注入时的关态串话为-19 dB。

一个检测半导体激光器质量的有效方法

对一百支PBC结构的InGaAsP/InP激光器的检测表明,通过变温的电导数及热阻测试给出的参数及参数随温度的变化可对半导体激光器有效地进行质量评价和可靠性筛选.

1.48μm掺铒光纤放大器泵源

用P型InP衬底新月型(PBC)结构制备1.48μm大功率激光,与单模光纤耦合输出功率大于40mW.

Defects in GaSb studied by coincidence Doppler broadening measurements

Undoped, Zn-doped and Te-doped GaSb with different concentrations were investigated by positron lifetime spectroscopy (PAS) and the Doppler broadening technique. Detection sensitivity of the latter technique was improved by using a second Ge-detector for the coincident detection of the second annihilation photon. PAS measurement indicated that there were vacancies in these samples. By combining the Doppler broadening measurements, the native acceptor defects in GaSb were identified to be predominantly Ga vacancy (V-Ga) related defects.

A novel high sensitivity CE-PTHPT for optical fiber communication

Planar punch through heterojunction phototransistors with a novel emitter control electrode and ion- implanted isolation (CE-PTHPT) are investigated. The phototransistors have a working voltage of 3-10V and high sensitivity at low input power. The base of the transistor is completely depleted under operating condition. Base current is zero. The CE-PTHPT has an increased speed and a decreased noise. The novel CE-PTHPT has been fabricated in this paper. The optical gain of GaAlAs/GaAs CE-PTHPT for the incident light power 1.3 and 43nw with the wavelength of 0.8 mu m reached 1260 and 8108. The input noise current calculated is 5.46 x 10(-16) A/H-z(1/2). For polysilicon emitter CE-PTHPT, the optical gain is 3083 at the input power of 0.174 mu w. The optical gain of InGaAs/InP CE-PTHPT reaches 350 for an incident power of 0.3 mu w at the wavelength of 1.55 mu m. The CE-PTHPT detectors is promising as photo detectors for optical fiber communication system.

High power continuous-wave operation of self-organized In(Ga)As/GaAs quantum dot lasers

Quantum dot (QD) lasers are expected to have superior properties over conventional quantum well lasers due to a delta-function like density of states resulting from three dimensional quantum confinements. QD lasers can only be realized till significant improvements in uniformity of QDs with free of defects and increasing QD density as well in recent years. In this paper, we first briefly give a review on the techniques for preparing QDs, and emphasis on strain induced self-organized quantum dot growth. Secondly, self-organized In(Ga)As/GaAs, InAlAs/GaAlAs and InAs/InAlAs Qds grown on both GaAs and InP substrates with different orientations by using MBE and the Stranski-Krastanow (SK) growth mode at our labs are presented. Under optimizing the growth conditions such as growth temperature, V/III ratio, the amount of InAs, InxGa1-xAs, InxAl1-xAs coverage, the composition x etc., controlling the thickness of the strained layers, for example, just slightly larger than the critical thickness and choosing the substrate orientation or patterned substrates as well, the sheet density of ODs can reach as high as 10(11) cm(-2), and the dot size distribution is controlled to be less than 10% (see Fig. 1). Those are very important to obtain the lower threshold current density (J(th)) of the QD Laser. How to improve the dot lateral ordering and the dot vertical alignment for realizing lasing from the ground states of the QDs and further reducing the Jth Of the QD lasers are also described in detail. Thirdly based on the optimization of the band engineering design for QD laser and the structure geometry and growth conditions of QDs, a 1W continuous-wave (cw) laser operation of a single composite sheet or vertically coupled In(Ga)As quantum dots in a GaAs matrix (see Fig. 2) and a larger than 10W semiconductor laser module consisted nineteen QD laser diodes are demonstrated. The lifetime of the QD laser with an emitting wavelength around 960nm and 0.613W cw operation at room temperature is over than 3000 hrs, at this point the output power was only reduced to 0.83db. This is the best result as we know at moment. Finally the future trends and perspectives of the QD laser are also discussed.

Yellow luminescence mechanism and persistent photoconductivity in n-GaN single crystal films grown on alpha-Al2O3(0001) substrates by LP-MOCVD

Unintentionally doped and Si-doped single crystal n-GaN films have been grown on alpha-Al2O3 (0001) substrates by LP-MOCVD. Room temperature photoluminescence measurement showed that besides the bandedges, the spectrum of an undoped sample was a broad deep-level emission band peaking from 2.19 to 2.30eV, whereas the spectrum for a Si-doped sample was composed of a dominant peak of 2.19eV and a shoulder of 2.32eV. At different temperatures, photoconductance buildup and its decay were also observed for both samples.. The likely origins of persistent photoconductivity and yellow luminescence, which might be associated with deep defects inclusive of either Ga vacancy(V-Ga)/Ga vacancy complex induced by impurities or N antisite (N-Ga), will be proposed.

Two-dimensional numerical simulation of the channel electron in an In0.52Al0.48As/In0.53Ga0.48As HEMT

A two-dimensional quantum model based on the solution of Schrodinger and Poisson equations is first presented for In0.52Al0.48As/In0.53Ga0.47As/InP HEMT. According to the model, the two-dimensional distributions of electron density and transverse electric field in the channel of InAlAs/InGaAs HEMT are discussed.

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.

Controllable growth of semiconductor nanometer structures

Self-assembled quantum dots and wires were obtained in the InxGa1-xAs/GaAs and InAs/In0.52Al0.48As/InP systems, respectively, using molecular beam epitaxy (MBE). Uniformity in the distribution, density, and spatial ordering of the nanostructures can be controlled to some extent by adjusting and optimizing the MBE growth parameters. In addition, some interesting observation on the InAs wire alignment on InP(001) is discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.

High-quality metamorphic HEMT grown on GaAs substrates by MBE

Metamorphic high electron mobility transistor (M-HEMT) structures have been grown on GaAs substrates by molecular beam epitaxy (MBE). Linearly graded and the step-graded InGaAs and InAlAs buffet layers hal e been compared, and TEM, PL and low-temperature Hall have been used to analyze the properties of the buffer layers and the M-HEMT structure. For a single-delta-doped M-HEMT structure with an In0.53Ga0.47As channel layer and a 0.8 mum step-graded InAlAs buffer layer, room-temperature mobility of 9000 cm(2)/V s and a sheet electron density as high as 3.6 x 10(12)/cm(2) are obtained. These results are nearly equivalent to those obtained for the same structure grown on an InP substrate. A basic M-HEMT device with 1 mum gate was fabricated, and g(m) is larger than 400 mS/mm. (C) 2001 Elsevier Science B.V. All rights reserved.