The influence of a c(2x2) ordered interface alloy of 3d transition metals at the ferromagnet/nonmagnet interface on interlayer exchange coupling (IXC), the formation of quantum well states (QWS) and the phenomenon of Giant MagnetoRe-sistance is investigated. We obtained a strong dependence of IXC on interface alloy formation. The GMR ratio is also strongly influenced. We found that Fe, Ni and C...

The effects of thermal annealing on the emission and microstructural characteristics of GaAs0.88Sb0.10N0.02/InP multiple quantum well (QW) structures were studied by photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The results show that the optimum annealing conditions lead to improved PL intensity accompanied by only a small blue shift, contrasting the behavior o...

A bottom-up approach for photonic crystal emitters and LEDs with semipolar quantum wells on large foreign substrates is presented. Structured c-oriented GaN/AlGaN templates are overgrown with GaN nanostripes and semipolar QWs emitting in the true-green spectral region. After embedding, the stripes and the growth mask act as one-dimensional (1D) photonic crystal. Electroluminescence shows bright...

We report on (a) the effect of growth interruption on the growth profile evolution in growth on non-planar patterned mesa tops via substrate-encoded size-reducing epitaxy (SESRE) and (b) the optical behavior of isolated 3D-confined GaAs volumes as well as 3D-confined GaAs volumes coupled with 1D-confined quantum wells (QWs) fabricated by SESRE. Steady-state excitation and time-resolved cathodol...

Time-resolved photoluminescence (PL) was applied to study the dynamics of carrier recombination in GaInNAsSb quantum wells (QWs) emitting near 1.3 μm and annealed at various temperatures. It was observed that the annealing temperature has a strong influence on the PL decay time, and hence, it influences the optical quality of GaInNAsSb QWs. At low temperatures, the PL decay time exhibits energy...

Metalorganic vapor phase epitaxy (MOVPE) nucleation studies of GaN on planar sapphire and nanopatterned AGOG (Deposition of Aluminum, Growth of Oxide, and Grain growth) sapphire substrates were conducted. The use of abbreviated GaN growth mode, which utilizes a process of using 15 nm low-temperature GaN buffer and bypassing etch-back and recovery processes during epitaxy, enables the growth of ...

This work focuses on investigations of the luminescence properties of coaxial InGaN layers around single GaN nano-tubes on top of GaN micro-pyramids. The nano-tube structure was formed after the controlled desorption of ZnO nano-pillar templates during the coaxial GaN epitaxy. An intense and broad photoluminescence (PL) peak centered around 2.85 eV is attributed to transitions from a shallow do...

We present the design and room-temperature lasing characteristics of single nanowires containing coaxial GaAs/AlGaAs multiple quantum well (MQW) active regions. The TE01 mode, which has a doughnut-shaped intensity profile and is polarized predominantly in-plane to the MQWs, is predicted to lase in these nanowire heterostructures and is thus chosen for the cavity design. Through gain and loss ca...

Double heterostructures of strained GaN quantum wells (QWs) sandwiched between relaxed AlN layers provide a platform to investigate the quantum-confined electronic and optical properties of the wells. The growth of AlN/GaN/AlN heterostructures with varying GaN quantum well thicknesses on AlN by plasma molecular beam epitaxy (MBE) is reported. Photoluminescence spectra provide the optical signat...

Spin photocurrents generated by homogeneous optical excitation with circularly polarized radiation in quantum wells (QWs) are reviewed. The absorption of circularly polarized light results in optical spin orientation due to the transfer of the angular momentum of photons to electrons of a two-dimensional electron gas (2DEG). It is shown that in quantum wells belonging to one of the gyrotropic c...