Novel Quaternary Dilute Magnetic Semiconductor (Ga,Mn)(Bi,As): Magnetic and Magneto-Transport Investigations

Magnetic and magneto-transport properties of thin layers of the (Ga,Mn)(Bi,As) quaternary dilute magnetic semiconductor grown by the low-temperature molecular-beam epitaxy technique on GaAs substrates have been investigated. Ferromagnetic Curie temperature and magneto-crystalline anisotropy of the layers have been examined by using magneto-optical Kerr effect magnetometry and low-temperature magneto-transport measurements. Postgrowth annealing treatment has been shown to enhance the hole concentration and Curie temperature in the layers. Significant increase in the magnitude of magnetotransport effects caused by incorporation of a small amount of Bi into the (Ga,Mn)As layers revealed in the planar Hall effect (PHE) measurements, is interpreted as a result of enhanced spin-orbit coupling in the (Ga,Mn)(Bi,As) layers. Two-state behaviour of the planar Hall resistance at zero magnetic field provides its usefulness for applications in nonvolatile memory devices.Comment: 10 pages, 3 figures, to be published in the Proceedings of ICSM-2016 conferenc

Effect of Misfit Strain in (Ga,Mn)(Bi,As) Epitaxial Layers on their Magnetic and Magneto-Transport Properties

Effect of misfit strain in the layers of (Ga,Mn)(Bi,As) quaternary diluted magnetic semiconductor, epitaxially grown on either GaAs substrate or (In,Ga)As buffer, on their magnetic and magneto-transport properties has been investigated. High-resolution X-ray diffraction, applied to characterize the structural quality and misfit strain in the layers, proved that the layers were fully strained to the GaAs substrate or (In,Ga)As buffer under compressive or tensile strain, respectively. Ferromagnetic Curie temperature and magnetocrystalline anisotropy of the layers have been examined by using magneto-optical Kerr effect magnetometry and low-temperature magneto-transport measurements. Post-growth annealing treatment of the layers has been shown to enhance the hole concentration and Curie temperature in the layers.Comment: 8 pages, 3 figure

Radiation hardness of AlAs/GaAs-based resonant tunneling diodes

The total dose effects of ⁶⁰Co γ-radiation on the electrical properties of double-barrier Resonant Tunneling Diodes have been studied. The devices manifest enhanced radiation hardness and conserve their operating parameters up to doses of 2×10⁹ rad. It is shown that all changes in the current-voltage characteristics stem from the effect of ionizing radiation on the undoped layers. The radiation-stimulated diffusion of the heteropair components in the contact region is shown to be important for the voltage drop distribution

Effect of rapid thermal annealing on properties of contacts Au-Mo-TiBx-GaAs

The analytical, structural and electrophysical techniques have been applied to studies of the thermal degradation mechanism appearing in diode structures with the Schottky barrier Au-Mo-TiBxGaAs. It was shown that the rapid thermal annealing at T = 600 °C during 60 sec in hydrogen atmosphere results in creating the ELS type center in the space charge region of GaAs. This center is represented by the complex VGa+VAs, which has been confirmed by photoluminescence measurements. It causes the appearance of excess current at the initial part of current-voltage characteristic

Electron Emission from Extended Defects in DLTS Experiment

Dislocations parallel to a Schottky junction are considered as an example of well defined extended defects, and their behaviour in DLTS experiment is examined. A possibility of electron hopping between different traps of the defect, and inter-electronic Coulomb interaction are taken into account. Thermal electron emission from the considered defects is no longer exponential with time and consequences of this fact are discussed

Quantum-Interference Semiconductor Devices Revisited

First, a simple semiclassical approach has been applied to the problem of a quantum phase acquired by an electron carrying both the charge and spin, which travels in an electromagnetic field. Basic hypothetical devices whose operation relies on the quantum interference, including spin-related interference, are discussed in the following. Finally, experimental results demonstrating two-beam interference in a planar quantum dot are presented

SPIN EFFECTS IN ELECTRON TRANSITIONS VIA DISLOCATION STATES IN SILICON

Nous discutons, dans ce papier, les résultats expérimentaux concernant la recombinaison dépendante du spin des porteurs de charge ainsi que de leur génération sur les dislocations dans le silicium. Nous proposons un modèle théorique tenant compte d'une interaction d'échange entre électrons pendants voisins. Ce modèle tient compte d'une part de la grande amplitude de cet effet et d'autre part de la variation en fonction de la température.Experimental results concerning spin-dependent recombination and generation of charge carriers at dislocations in silicon are discussed. A theoretical model taking into account an exchange interaction between neighbouring dangling electrons is considered. It is shown that this model can account for both the large magnitude of the effect and its temperature variation

Transit Time of Electron Tunneling Through a Potential Barrier

The average transit time of electron tunneling through a potential barrier is newly defined and examined without using the concept of a wave packet and without solving explicitly the time dependent Schrödinger equation