We investigated experimentally and theoretically the valence-band structure of wurtzite InP nanowires. The phase, which usually is not stable for III-V phosphide compounds, has been observed in present results on electronic properties these nanowires using photoluminescence excitation technique. Spectra from an ensemble show three clear absorption edges separated by 44 meV 143 meV, respectively. band are attributed to excitonic absorptions involving distinct valence-bands labeled: A, B, C....

We report polarized Raman scattering and resonant studies on single InAs nanowires. Polarized experiments show that the highest intensity is obtained when both incident analyzed light polarizations are perpendicular to nanowire axis. wurtzite optical modes observed. The consistent with selection rules also results of calculations using an extended rigid-ion model. Additional reveal a redshifted ${E}_{1}$ transition for nanowires compared bulk zinc-blende due dominance phase in Ab initio...

We report electric-field-induced modulation of the spin splitting during charging and discharging processes a $p$-type $\mathrm{GaAs}∕\mathrm{AlAs}$ double-barrier resonant-tunneling diode under an applied bias magnetic field. In addition to conventional Zeeman effect, we find experimental evidence excitonic produced by combination Rashba spin-orbit interaction, Stark charge accumulation. The abrupt changes in photoluminescence with provide information about accumulation effects device.

Most III-V semiconductors, which acquire the zinc-blende phase as bulk materials, adopt metastable wurtzite when grown in form of nanowires. These are new semiconductors with optical properties, particular, a different electronic band gap compared that phase. The InAs at Gamma-point Brillouin zone (E0 gap) has been recently measured, E0 = 0.46 eV low temperature. A point (equivalent to L structure, E1) also obtained based on resonant Raman scattering experiment. In this work, we calculate...

We present variational calculations of the binding energy for positively and negatively charged excitons (trions) in idealized ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$ quantum wells with parabolic electrons holes dispersions. The configuration interaction method is used a physically meaningful single-particle basis set. have shown that inclusion more than one electron quantum-well solution important to obtain accurate values...

We present a model that takes into account the interface-defects contribution to binding energy of charged excitons (trions). use Gaussian defect potentials and one-particle basis set. All Hamiltonian terms are analytically calculated for s-like trial wave functions. The dependence trion size on quantum-well width investigated using variational method ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$ quantum wells. show even in case...

The existence of polytypism in semiconductor nanostructures gives rise to the appearance stacking faults which many times can be treated as quantum wells. In some cases, despite a careful growth, hardly avoided. this work, we perform an ab initio study zincblende wurtzite InP system, using supercell approach and taking limit low density narrow regions. Our results confirm type II band alignment between phases, producing reliable qualitative description gap evolution along growth axis. These...

With the solution of Schr\"odinger equation for electrons in three-dimensional (3D) hard wall quantum channels, conductance semiconductor nanowires is studied as a function length, size, and contact dimensionality. Within envelope approximation, two-terminal Landauer--B\"uttiker has been calculated ballistic regime, using mode matching technique. The contacts are modeled by semi-infinite regions with confinement along only one transverse directions, so that continuous crossover from...

In the present work single-quantum-well laser diodes operating at 0.98 μm are investigated by photothermal reflectance microscopy. Temperature maps were obtained for output facet of all devices studied. Furthermore, temperature distribution was determined along cavity (on ridge) lasers soldered with junction side up. Near facets, measured found to be about seven times bulk’s temperature, indicating presence an important surface heat source. The signal phase shows role vertical structure on...

Metallic uranium is very reactive at the high temperatures used for its processing [1]; therefore special refractory crucibles must be employed. This work presents a comparative study among coatings, wich are in of metallic temperature above melting point. In this work, samples uranium, without any superficial oxide layer, were placed on sample holders coated with alumina, magnesium and alumina titanium nitride, thermally treated vacuum furnace. The kept certain determined time intervals...

Indium arsenide nanowires were synthesized with an intermixing of wurtzite and zincblende structure by chemical beam epitaxy the vapor‐liquid‐solid mechanism. Resonant Raman spectroscopy transverse optical phonon mode at 215 cm−1 reveals E1 gap 2.47 eV which is assigned to electronic band A point in indium phase.

We calculate the conductance of three-dimensional semiconductor quantum wires considering different effective masses in contacts and channel. show that, with respect to case equal channel contacts, amplitude oscillations increases if electron mass is larger decreases it smaller than contacts. Effects on density probability are also shown. These effects discontinuity explained terms kinetic confinement transmission coefficient modulation.

In this paper, we present a novel model to compute dark current in quantum well infrared photodetectors (QWIP) the thermionic regime, based on Ehrenfest theorem and with no adjusting parameter. model, operator of linear momentum is used obtain carriers velocity above barrier level. The wave functions are calculated considering non-parabolic approximation temperature-dependent gap energy. theoretical results compared experimental data obtained from conventional AlGaAs/GaAs QWIPs rectangular...

We present the effects of center-of-mass dynamics on negatively charged exciton bound states in presence longitudinal magnetic and electric fields. consider an idealized ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$ quantum well low-field limit use configuration interaction method to build up two-particle basis set. Our results show that center mass has be taken into account for a realistic description states.

We propose a semiconductor heterostructure that allows an effective control of the shape carriers wavefunctions by varying just one main structural parameter. The structure is formed type II quantum dot and I well. present results calculations for particular system consisting InP/GaAs InGaAs/GaAs well using simple mass model provides good insight on our structure. show wavefunction carrier remains outside changes from spheroidal to ring‐like depending mainly separation between layers. This...

We present variational calculations of the binding energy for negatively charged donors in GaAs/Al0.3Ga0.7As quantum wells. show that electronic well ground state and parabolic dispersions are enough to obtain accurate results compared with previous Monte Carlo calculations. The configuration interaction method is used a physically meaningful basis set. study donor dependence on width position presence external electric magnetic fields.

We present a model to take into account the interface defects contribution on binding energy of charged exciton in GaAs/Al0.3Ga0.7As quantum wells. The dependence gain and trion size well width are variationally calculated. show that is more sensitive than exciton.

The influence of dimensionality on the conductance semiconductor cross junctions is investigated in effective mass approximation and quantum ballistic regime. Our calculations exhibit some similar features for both two- three-dimensional models, namely peaks before fundamental eigenenergy wire that represents sidearms zero dip. Despite this, we show that, general, electronic wave function are strongly affected when third spatial dimension taken into account. In other words, prove...