Room-temperature continuous-wave operation of InAs quantum-wire laser on InP(001) substrate

A self-assembled quantum-wire laser structure was grown by solid-source molecular beam epitaxy in an InAlGaAs-InAlAs matrix oil InP(001) substrate. Ridge-waveguide lasers were fabricated and demonstrated to operate at a heatsink temperature tip to 330 K in continuous-wave (CW) mode. The emission wavelength of the lasers with 5 mm-long cavity was 1.713 mu m at room temperature in CW mode. The temperature stability of the devices was analysed and the characteristic temperature was found to be 47 K in the mnge of 220-320 K.

Large g factors of higher-lying excitons detected with reflectance difference spectroscopy in GaAs-based quantum wells

Exciton g factors in GaAs-based quantum wells (QWs) were evaluated by reflectance difference spectroscopy (RDS) under a weak magnetic field. The well-width dependence of the n=1 heavy-hole exciton (1H1E) g factor agrees well with the reported results, demonstrating RDS as a sensitive tool for detection of g factor. By comparison, the n=1 light-hole exciton g factor increases with the well width, and shows a larger value than that of 1H1E. In a 20-nm-wide Al0.02Ga0.98As/AlAs multiple QW sample, the g factors of up to ten excitons are obtained, and the higher-lying exciton g factors are found to be one order larger than that of the 1H1E exciton.

Photocurrent response in a double barrier structure with quantum dots-quantum well inserted in central well

We report the photocurrent response in a double barrier structure with quantum dots-quantum well inserted in central well. When this quantum dots-quantum well hybrid heterostructure is biased beyond + 1 or -I V, the photocurrent response manifests itself as a steplike enhancement, increasing linearly with the light intensity. Most probably, at proper bias condition, the pulling down of the X minimum of GaAs at the outgoing interface of the emitter barrier by the photovoltaic effect in GaAs QW will initiate the r,-X-X tunneling at much lower bias as compared with that in the dark. That gives rise to the observed photocurrent response. (c) 2006 Elsevier B.V. All rights reserved.

Optical properties and g factors of GaAs quantum rods

The Hamiltonian of the zinc-blende quantum rods in the framework of eight-band effective-mass approximation in the presence of external homogeneous magnetic field is given. The electronic structure, optical properties and electron g factors of GaAs quantum rods are investigated. We found that the electron g factors are very sensitively dependent on the dimensions of the quantum rods. As some of the three dimensions increase, the electron g factors decrease. The more the dimensions increase, the more the electron g factors decrease. The dimensions perpendicular to the direction of the magnetic field affect the electron g factors more than the other dimension. (c) 2006 Elsevier B.V. All rights reserved.

Optical manipulation of single electron spin in doped and undoped quantum dots

The optical manipulation of electron spins is of great benefit to solid-state quantum information processing. In this letter, we provide a comparative study on the ultrafast optical manipulation of single electron spin in the doped and undoped quantum dots. The study indicates that the experimental breakthrough can be preliminarily made in the undoped quantum dots, because of the relatively less demand.