Room-temperature yellow-orange (In,Ga,Al)P–GaP laser diodes grown on (n11) GaAs substrates
We report room temperature injection lasing in the yellow–orange
spectral range (599–605 nm) in (AlxGa1–x)0.5In0.5P–GaAs diodes with 4 layers of tensilestrained
InyGa1–yP quantum dot-like insertions. The wafers were grown by metal–organic
vapor phase epitaxy side-by-side on (811), (211) and (322) GaAs substrates tilted towards the
<111> direction with respect to the (100) surface. Four sheets of GaP-rich quantum barrier
insertions were applied to suppress leakage of non-equilibrium electrons from the gain
medium. Laser diodes having a threshold current densities of ~7–10 kA/cm2 at room
temperature were realized for both (211) and (322) surface orientations at cavity lengths of
~1mm. Emission wavelength at room temperature ~600 nm is shorter by ~8 nm than
previously reported. As an opposite example, the devices grown on (811) GaAs substrates did
not show lasing at room temperature.
The conference was held in the form of lectures by leading scientists, oral and poster presentations of young scientists and students of physical specialties, as well as leaders of innovative structures for the purpose of mutual acquaintance with the new results of fundamental research on a wide range of areas in physics, the prospects and challenges in the expansion of relations between science , education and high technologies. SECTION (heads): I. LASERS (Fundam. Probl., Computer ...) (prof. A.A.Ionin) II. OPTICS (quant., And nano materials and new sources) (d.f.m.n.A.V.Masalov) III. Solid state physics, INCLUDING Nanostructures ELEM. BASE UNIT (Corresponding Member of RAS N.N.Sibeldin) IV. Nuclear physics, high energy physics (prof. O.D.Dalkarov, Head: Prof. V.A.Ryabov) V. PLASMA PHYSICS and particle beams (Head: Prof. A.V.Agafonov) VI. Astrophysics (Head: Prof. S.A.Bogachev) VII. PHYSICS IN THE MODERN INSTRUMENT AND TECHNOLOGY (prof. V.N.Nevolin)
We report on broad-area lasers, mode-locked lasers (MLLs), and superluminescent light-emitting diodes (SLDs) based on a recently developed novel type of nanostructures that we refer to as quantum well-dots (QWDs). The QWDs are intermediate in properties between quantum wells and quantum dots and combine some useful properties of both. 1.08 μm InGaAs/GaAs QWDs broad area edge-emitting lasers based on coupled large optical cavity waveguides show high internal quantum efficiency of 92%, low internal loss of 0.9 cm-1 and material gain of ~1.1∙104 cm-1 per one QWD layer. CW output power of 14.2 W is demonstrated at room temperature. Superluminescent light-emitting diodes with one QWD layer in the active region exhibit stimulated emission spectra centered at 1050 nm with the maximal full width at half maximum of 36 nm and the output power of 17 mW. First results on mode-locked operation in QWD lasers are also presented. 2 mm long two-section devices demonstrate the pulse repetition rate of 19.3 GHz and the pulse duration of 3.5 ps. The width of the radio frequency spectrum is 0.2 MHz.
A theoretical model is suggested to determine the critical conditions for generation of circular prismatic misfit dislocation loops in hollow core-shell nanoparticles. Based on a strict solution of the linear elasticity boundary-value problem for a circular prismatic dislocation loop in a free-surface shell, we examine the loop formation energy in the nanoparticle and show a potential opportunity to fabricate hollow coherently bonded, i.e. dislocation-free, core-shell nanoparticles by using thin-wall shells with inner-to-outer radii ratio larger than 0.8 as supporting cores.
We demonstrate evidence of coherent magnetic flux tunneling through superconducting nanowires patterned in a thin highly disordered NbN film. The phenomenon is revealed as a superposition of flux states in a fully metallic superconducting loop with the nanowire acting as an effective tunnel barrier for the magnetic flux, and reproducibly observed in different wires. The flux superposition achieved in the fully metallic NbN rings proves the universality of the phenomenon previously reported for InOx .We perform microwave spectroscopy and study the tunneling amplitude as a function of the wire width, compare the experimental results with theories, and estimate the parameters for existing theoretical models.
The results of measurements of an electron density in a microwave plasma filament in dense gas (argon) are reported. The electron density has been determined on the basis of Stark broadening of lines detected in the absorption spectrum. A high-resolution spectrometer incorporating GaAlAs diode laser operating at 870 nm has been used to measure Stark broadening and shifts of the argon line. The electron density in the filament was found to increase from the initial level of 10 exp 12/cu cm to value n sub e greater than 10 exp 16/cu cm. The dependencies of the electron density on gas pressure and microwave power density are presented.
The possibilities of computer experiments performed with the MDSLAGMELT v. 10.0 information-research system (IRS) with remote access are described. The main classes of mathematical models and methods and the sets of properties obtained in computer experiments are considered. An information model is developed for an oxide melt to study multidimensional composition–temperature–property–structure relations. A nanostructural model based on generalized graph network descriptors is considered in detail. The results of simulating the structure-sensitive properties of the SiO2–Na2O system using IRS are presented.
This book presents research dedicated to solving scientific and technological problems in many areas of electronics, photonics and renewable energy. Progress in information and renewable energy technologies requires miniaturization of devices and reduction of costs, energy and material consumption. The latest generation of electronic devices is now approaching nanometer scale dimensions; new materials are being introduced into electronics manufacturing at an unprecedented rate; and alternative technologies to mainstream CMOS are evolving. The low cost of natural energy sources have created economic barriers to the development of alternative and more efficient solar energy systems, fuel cells and batteries.
Nanotechnology is widely accepted as a source of potential solutions in securing future progress for information and energy technologies. Nanoscale Materials and Devices for Electronics, Photonics and Solar Energy features chapters that cover the following areas: atomic scale materials design, bio- and molecular electronics, high frequency electronics, fabrication of nanodevices, magnetic materials and spintronics, materials and processes for integrated and subwave optoelectronics, nanoCMOS, new materials for FETs and other devices, nanoelectronics system architecture, nano optics and lasers, non-silicon materials and devices, chemical and biosensors,quantum effects in devices, nano science and technology applications in the development of novel solar energy devices, and fuel cells and batteries.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.