Transient negative photocurrent and out-of-well dipole kinetics in novel piezoelectric InGaAs/GaAs MQW pin diodes

In 111B InGaAs/GaAs pin structures with a multiple quantum well (MQW) embedded region, the average internal field in the active MQW region can be tailored to obtain device configurations with a negative average field (NAF), opposite to the built-in field. In 111 NAF diodes, carriers photogenerated at the wells become trapped early at the potential minima located at the ends of the active region thus creating an electric dipole. In this work, in 111 NAF devices with a 0.17 In mole fraction layers, by using time-resolved photocurrent and a novel optical-pump electrical-probe techniques, we report the presence of a negative transient photocurrent, a direct quantitative evidence of such dipole formation, and we present measurements of its extinction kinetics at room temperature.     

Design and Characteristics of InGaAs/GaAs MQW SEED Arrays Structure

讨论了谐振腔中的DBR对InGaAs／GaAs多量子阱SEED面阵光反射特性的影响．采用InGaAs／GaAs作为多量子阱SEED器件的有源区,从而获得了980nm工作波长．设计和分析了InGaAs／GaAs多量子阱SEED中的一种用于倒装焊的新型谐振腔结构．多量子阱材料是用MOCVD系统生长,利用微区光反射谱、PL谱以及X射线双晶衍射对多量子阱材料进行了测量和分析,测量结果表明多量子阱材料具有良好的质量,证明了器件结构的设计和分析是准确的．     

InGaAs/GaAs多量子阱SEED面阵结构特性与设计

讨论了谐振腔中的 DBR对 In Ga As/ Ga As多量子阱 SEED面阵光反射特性的影响 .采用 In Ga As/ Ga As作为多量子阱 SEED器件的有源区 ,从而获得了 980 nm工作波长 .设计和分析了 In Ga As/ Ga As多量子阱 SEED中的一种用于倒装焊的新型谐振腔结构 .多量子阱材料是用 MOCVD系统生长 ,利用微区光反射谱、PL 谱以及 X射线双晶衍射对多量子阱材料进行了测量和分析 ,测量结果表明多量子阱材料具有良好的质量 ,证明了器件结构的设计和分析是准确的     

MOCVD-grown broad area InGaAs/GaAs/InGaP laser diodes

A MOCVD technology for growth of InGaAs/GaAs/InGaP laser heterostructures on a modified Epiquip VP-50-RP installation was developed. Mesa stripe laser diodes with threshold current density J _th=100–200 A/cm², internal optical loss α_i=1.3–1.7 cm^?1, and internal quantum efficiency η_i=60–70% have been fabricated. A CW output optical power of 5 W has been obtained for a single 100-µm-wide aperture mesa stripe laser diode emitting at 1.03 µm. It is shown that use of AlGaAs waveguide layers, which increase the conduction band barrier offset, lowers the temperature sensitivity of laser heterostructures within the temperature range 10–80°C.     

Charge accumulation effects in InGaAs/GaAs [111]-oriented piezoelectric multiple quantum wells

We show that charge accumulation in piezoelectric [111]-oriented multiple quantum wells (MQWs), with average electric fields opposing the field in the barriers, inhibits the shift of optical transitions by externally applied electric fields. This effect is due to the screening of the average electric field as photogenerated electrons and holes drift towards the opposite edges in the MQW region due to this average field. The resulting dipole flattens the envelope potential and hence precludes the change of energy levels with variations of external voltage. This behavior has been observed in different device configurations employing InGaAs/GaAs MQW embedded in a p-i-n diode by low temperature photoluminescence (PL) and photocapacitance spectroscopies under different bias conditions. In addition to these ‘self-locked’ transitions we also observed other peaks in the PL spectra related to the charge accumulation effect and that are qualitatively explained using Hartree calculations.     

Differential capacitance measurements of relaxation-induced defectsin InGaAs/GaAs Schottky diodes

The use of a differential capacitance technique for characterizing the relaxation-induced defect states in Schottky diodes has been studied. Based on a proposed equivalent circuit including the effect of potential drop across the carrier-depletion layer, a simple equation of capacitance at different voltages and frequencies is derived and compared with experimental data obtained from relaxed In_0.2Ga _0.8As/GaAs samples. It is shown that the carrier-depletion layer will introduce capacitance dispersion over frequency like traps; from it the device's geometric parameters, the resistance of the carrier-depletion layer and the ionization energy of the deep level that gives rise to this resistance can be obtained. The relation between the low-frequency capacitance and reverse voltage can be explained well by the depletion of the free carriers between the Schottky depletion and the carrier-depletion layer. The relaxation-induced traps are believed to be at 0.535 and 0.36 eV, respectively, in the GaAs and In_0.2 Ga_0.8As regions     

Chemical and phase composition of GaMnAs/GaAs/InGaAs spin light-emitting diodes

The technique of X-ray photoelectron spectroscopy combined with ion profiling is used for the quantitative chemical analysis of the structure of spin light-emitting diodes with a GaMnAs spin-injection layer and an InGaAs quantum well. The depth distribution of phases is determined, and the causes of redistribution of the phases are clarified. In the spin-injection layer, the fractions of antiferromagnetic Mn and ferromagnetic MnAs are at the same level. The procedure for phase separation and verification of the correctness of determination of the content of components is improved.     

Double-heterostructure InGaAs/InP PIN photodetectors

High-quality n⁺InP/InGaAs/p⁺InP double-heterojunction PIN photodetectors have been grown by special liquid-phase-epitaxial techniques. This development allows front illumination which substantially facilitates device fabrication and operation. Furthermore, good control of pn junction location and layer thickness in these structures permits optimization of high-speed performance. For convenient device areas, low dark-current densities (2.5×10⁻⁵ A/cm²) and short response-times (50 ps) are obtained. High-speed design parameters are discussed, and the reduction of response times to 30 ps is predicted.     

Implant Compositional Disordering on InGaAs／InP MQW Structures

ＩｍｐｌａｎｔＣｏｍｐｏｓｉｔｉｏｎａｌＤｉｓｏｒｄｅｒｉｎｇｏｎＩｎＧａＡｓ／ＩｎＰＭＱＷＳｔｒｕｃｔｕｒｅｓ￥ＺＨＡＯＪｉｅ；ＬＩＵＢａｏｊｕｎ；ＷＡＮＧＹｕｆａｎｇ；ＷＡＮＧＹｕｏｎｇｃｈｅｎ；ＴｈｏｍｐｓｏｎＤＡ（ＴｉａｎｊｉｎＮｏｒｍａｌＵ...     

单片InGaAs／InP PIN PD阵列

文章简要地介绍了ＩｎＧａＡｓ／ＩｎＰ ＰＩＮ ＰＤ阵列的制作现状及其应用和发展趋势。     

Observation of the pyroelectric effect in strained piezoelectric InGaAs/GaAs quantum-wells grown on (111) GaAs substrates

We investigated the temperature dependence of the piezoelectric constant e₁₄, i.e. the pyroelectric effect, of various strained InGaAs/GaAs single- and multi-quantum wells embedded in p-i-n structures grown on (111)B GaAs substrates and diodes made from these structures. Both photoreflectance spectroscopy and differential photocurrent spectroscopy were applied to obtain e₁₄ over the temperature range 11-300 K. The values of e₁₄ for In_xGa_1−xAs quantum well layers with x=0.12-0.21 were observed to increase with temperature, which is contrary to the expected dependence, and the strain-induced components of the pyroelectric coefficients were quantitatively determined. The dependence of the pyroelectric coefficient on In fraction is discussed.     

Growth and characterization of (111)B InGaAs/GaAs multi-quantum well PIN diode structures

High quality piezoelectric strained InGaAs/GaAs multi-quantum well structures on (111)B GaAs substrates have been grown by solid-source molecular beam epitaxy in a PIN configuration. 10K photoluminescence (PL) shows narrow peaks with widths as low as 3 meV for a 25-period structure while room temperature (RT) PL shows several higher order peaks, normally forbidden, indicating breaking of inversion symmetry by the piezoelectric field. Furthermore, both the 10K PL peak position and the form of the RT PL spectra depend on the number of quantum wells within the intrinsic region, suggesting that the electric-field distribution is altered thereby. Diodes fabricated from these structures had sharp avalanche breakdown voltages (V_bd) and leakage currents as low as 8 × 10⁻⁶ A/cm² at 0.95 V_bd, indicating quality as high as in (100) devices. On leave from: Department de Ingeniera Electronica, Universidad Politecnica de Madrid, Madrid, Spain.     

Hot-electron effects on AlGaAs/InGaAs/GaAs PHEMTs under accelerated DC stresses

The behavior of Schottky gate characteristics before and after hot-electron stress has been a relatively neglected topic. Thus, this paper discussed the effects of hot-electron accelerated stress on the DC characteristics of AlGaAs/InGaAs/GaAs PHEMTs as they relate to Schottky gate characteristics. It also presents studies of reverse Schottky gate characteristics before and after hot-electron stresses, as related to two major mechanisms: (1) the widening of the depletion region under the gate; and (2) the impact of the carriers trapped under the gate. The former induces a larger Schottky barrier height with a smaller reverse leakage current density than the latter, while the latter induces the opposite. Two hot-electron conditions are used to investigate the impact of the hot-electron stress on the gate leakage current. The gate leakage current decreases after a hot-electron stress, due the effect of hot-electron stress on the Schottky diode characteristics. Moreover, improvement in the noise performance is expected, due to the decrease in the gate leakage current. Both pre- and post-stress noise measurements have been done to demonstrate this.     

Monolithic integration of InGaAs/InP DFB lasers and InGaAs/InAlAs MQW optical modulators

The first successful monolithic integration of InGaAsP/InP distributed feedback (DFB) lasers and InGaAs/InAlAs multiple quantum well (MQW) optical modulators using LPE (liquid phase epitaxy)/MBE (modlecular beam epitaxy) hybrid growth reported. A 14% light output modulation is observed in this integrated device.     

A planar InGaAs PIN/JFET fiber-optic detector

A planar structure monolithic optoelectronic integrated circuit (OEIC), comprising an InGaAs PIN photodiode and an InGaAs junction field effect transistor (JFET), has been developed. A cutoff frequency of 1.3 GHz has been successfully obtained. A low dark-current characteristic has also been obtained by polyimide passivation. Design principle, fabrication procedures, and operation characteristics of the PIN/JFET are described.     

Barrier width dependence of leakage currents in InGaAs/ GaAs multiple quantum well P-I-N diodes

A range of InGaAs/GaAs strained layer multiple quantum well pin diode structures with different barrier dimensions has been grown and characterized. High quality low leakage structures (< 2 × 10⁻⁴ A/cm² @ 0.9 V _BD ) with a high degree of strain (∼2%) have been produced. An important factor affecting the leakage for a fixed well composition and dimension is found to be the barrier width.     

Radiative and nonradiative recombination in the active layers of high-power InGaAs/GaAs/AlGaAs laser diodes

Recombination rates due to radiative and nonradiative processes and the rate of recombination induced by amplified luminescence have been determined for lasers based on an asymmetric InGaAs/GaAs/AlGaAs heterostructure with an ultrawide waveguide in the subthreshold region. It is shown that the quantum efficiency of luminescence is no less than 91.5% for the laser samples studied.     

Nonlinear-optical effects in semiconductor lasers based on InGaAs/GaAs/AlGaAs quantum-confinement heterostructures

Generation of a difference-frequency wave by two electromagnetic waves propagating in a heterolaser is analyzed theoretically. Calculations are carried out for InGaAs/GaAs/AlGaAs heterostructures of design optimized to attain maximum lasing power. It is shown that phase matching between the primary waves and the difference-frequency wave may persist over a distance of ～1 mm, comparable to the cavity length (2–3 mm), and the conversion coefficient can be as large as several percent.     

Cathodoluminescence study of pyramidal facets in piezoelectric InGaAs/GaAs multiple quantum well pin photodiodes

A study of the optical and electrical activity of defects at the surface of InGaAs/GaAs multiple quantum well pin photodiodes was done on two different misoriented (111)B GaAs substrates: substrate A, misoriented 1° towards [2̄11] and substrate B, misoriented 2° towards [21̄1̄]. In this article, we report the existence of different faceted defects at the surface with the misorientation and their influence on the optical performance. The surface of photodiodes grown on substrate A shows inclined pyramids with two enhanced facets. The electron beam induced current measurements showed that these pyramids act as high efficient collector of the e-beam excited electron–hole pairs (e–h). This behaviour agrees with the reduction of the cathodoluminescence emission efficiency at the facets. In contrast, a different pyramid type with one enhanced facet is observed at the surface of diodes grown on substrate B. However, these facets have not shown either optic or electric activity. In these diodes, the dislocations localised at the active region degrade the device performance acting as non-radiative recombination centres.