Spectroscopic characterization of 1.3µm GaInNAs quantum-well structures grown by metal-organic vapor phase epitaxy

We report optical studies of high-quality 1.3 μm strain-compensated GaInNAs/GaAs single-quantum-well structures grown by metalorganic vapor phase epitaxy. Photoluminescence excitation (PLE) spectroscopy shows clearly the electronic structure of the two-dimensional quantum well. The transition energies between quantized states of the electrons and holes are in agreement with theoretical calculations based on the band anti-crossing model in which the localized N states interact with the extended states in the conduction band. We also investigated the polarization properties of the luminescence by polarized edge-emission measurements. Luminescence bands with different polarization characters arising from the electron to heavy-hole and light-hole transitions, respectively, have been identified and verify the transition assignment observed in the PLE spectrum

Group theory in the Jahn-Teller effect

LD:D45853/83 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Influence of composition diffusion on the band structures of InGaNAs/GaAs quantum wells investigated by the band-anticrossing model

We investigate the influence of quantum-well intermixing (QWI) on the electronic band structure of GaInNAs/GaAs multiquantum wells. The band structures and optical transitions have been calculated based on the band-anticrossing (BAC) model and Fick's interdiffusion law for both intermixed and nonintermixed samples, respectively. The calculated results are consistent with the true optical transitions observed by photoluminescence excitation spectroscopy and secondary ion mass spectroscopy. Our investigation indicates that BAC model is valid for interdiffused quantum wells and verifies that the QWI process in GaInNAs/GaAs multiquantum wells is induced mainly by the interdiffusion of In-Ga between the quantum wells and barriers

N-N pair effects on GaInNAs semiconductor optical amplifiers

We explore the effects of N-N pairs on the amplifying properties of GaInNAs based Semiconductor Optical Amplifiers. The bandstructure of GaInNAs is calculated with the 3 band anti-crossing model to account for the N-N pairs for the conduction band and k-p theory for the valence bands. For the calculation of the GaInNAs amplifier properties we adopt a multi-sectioning approach to the rate equation that accounts for amplified spontaneous emission. Based on these we discuss the merits of N-N pairs for GaInNAs semiconductor optical amplifiers. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA

Simulation of gain and modulation bandwidths of 1300nm RWG InGaAsN lasers

The gain and dynamic behaviour of InGaAsN quantum well (QW) lasers is investigated. A comparison of simulated material gain of 1300 nm InGaAsN, AlGaInAs and InGaAsP quantum wells is made to gauge its gain performance. The small-signal modulation characteristics of a 250 µm MQW ridge waveguide (RWG) InGaAsN laser are presented and high-temperature characteristics are shown

Quantum-well intermixing influence on GaInNAs/GaAs quantum-well laser gain: theoretical study

The effect of quantum-well intermixing on the material gain of a GaInNAs/GaAs quantum-well laser is investigated theoretically. The diffusion of gallium and indium atoms in the intermixed sample is assumed and their compositional profiles are modelled using Fick's law. The band-anti-crossing model is used to calculate the band structure of the GaInNAs quantum well, which is appropriate for this non-randomly-alloyed material system. The calculated results show good agreement with the observed photoluminescence excitation for both non-intermixed and intermixed samples, which confirms this model. It is found that the strain gradient, the variation of material band gap and the degeneracy between heavy and light holes are the main factors determining the quantized energy levels of the intermixed quantum well. With the increase of diffusion length, the material gain and differential gain decrease due to the increase of the conduction band effective mass and the rapid decrease of the dipole moments. These characteristics of quantum-well intermixing effects will be useful in the design of integrated photonic devices based on this material. (Abstract from WOK

Quantum-well intermixing influence on GaInNAs/GaAs quantum-well laser gain: theoretical study

The effect of quantum-well intermixing on the material gain of a GaInNAs/GaAs quantum-well laser is investigated theoretically. The diffusion of gallium and indium atoms in the intermixed sample is assumed and their compositional profiles are modelled using Fick's law. The band-anti-crossing model is used to calculate the band structure of the GaInNAs quantum well, which is appropriate for this non-randomly-alloyed material system. The calculated results show good agreement with the observed photoluminescence excitation for both non-intermixed and intermixed samples, which confirms this model. It is found that the strain gradient, the variation of material band gap and the degeneracy between heavy and light holes are the main factors determining the quantized energy levels of the intermixed quantum well. With the increase of diffusion length, the material gain and differential gain decrease due to the increase of the conduction band effective mass and the rapid decrease of the dipole moments. These characteristics of quantum-well intermixing effects will be useful in the design of integrated photonic devices based on this material. (Abstract from WOK

Quantum-well intermixing influence on GaInNAs/GaAs quantum-well laser gain: theoretical study

The effect of quantum-well intermixing on the material gain of a GaInNAs/GaAs quantum-well laser is investigated theoretically. The diffusion of gallium and indium atoms in the intermixed sample is assumed and their compositional profiles are modelled using Fick's law. The band-anti-crossing model is used to calculate the band structure of the GaInNAs quantum well, which is appropriate for this non-randomly-alloyed material system. The calculated results show good agreement with the observed photoluminescence excitation for both non-intermixed and intermixed samples, which confirms this model. It is found that the strain gradient, the variation of material band gap and the degeneracy between heavy and light holes are the main factors determining the quantized energy levels of the intermixed quantum well. With the increase of diffusion length, the material gain and differential gain decrease due to the increase of the conduction band effective mass and the rapid decrease of the dipole moments. These characteristics of quantum-well intermixing effects will be useful in the design of integrated photonic devices based on this material. (Abstract from WOK

Optical transitions in GaInNAs/GaAs multi-quantum wells with varying N content investigated by photoluminescence excitation spectroscopy

We report on the nitrogen-concentration dependence of optical transitions between quantized states of electrons and holes in GaInNAs/GaAs multi-quantum wells. Using low-temperature photoluminescence excitation spectroscopy, systematic studies have been performed on a series of samples with nitrogen concentrations in the range 0%-1.14%. The observed data were compared with theoretical fitting based on the band anticrossing model in which the localized N states interact with the extended states in the conduction band, taking strain effects into account. Our results are consistent with the band anticrossing model, but with differing coupling strength between different quantum states of electrons in the quantum wells